Thanks for that additional information. It doesn't sound like she has had a lot of socialization at all. There are things you can do though.
The first thing you should do is start obedience training. Obedience training is not just to teach commands. It is also for establishing yourself as the boss and leader. This is important because a dog looks to the boss to determine how they should react to other dogs, people and new situations. I should also let you know that if you are worried about how your new dog will act, she will pick up on that feeling and actually get worse as she feels that the dog is the reason you are worried.
The following site is helpful in helping owners train their dog. Be sure and click on the link to the page on obedience at the bottom. and links on subsequent pages leading to detailed instructions.
Training works best if you train at least 30 minutes a day (two 15 minute sessions). I would start making your dog work via the Nothing in life is free program (NILF). It is outlined below.
You practice the same commands over and over again until the dog is conditioned to obey them immediately. Initially a dog does this for the treats but each time they obey, it makes them a little more submissive to you and makes you the boss. As the boss, your dog will look to you to determine how she should react.
The other thing is to work on a good leash walk with her. The front clip harness is a great idea. I love that they pull a dog around to face you when they lunge or pull too hard. I have a write up I use for leash training for my clients. I'm going to include it below so I don't forget to include any points.
Leash training brochure
If your dog is pulling while walking then a little retraining is in order. It's a matter of getting your dog to want to come with you regardless of the leash being attached. You will get multiple answers depending on whom you talk to as opinions differ on the best method to solve this problem. Some experts will suggest a Halti (head collar) which you can try. I personally believe in establishing control over the dog with training. I use a chain collar for training purposes. For strong stubborn dogs, some trainers recommend a prong collar.
Number one, put your dog on a leash before leaving the house. Make your dog sit or lie down before leaving. You walk out first and the dog should follow you out. With a proper walk, the dog should be right at your side or slightly behind. You dog should be paying attention to you, frequently glancing at you to be sure you haven't changed your mind about where you are going. I will be using the word correction. A correction will indicate a short quick tug and release of the leash. It is meant to remind the dog that she is supposed to be paying attention to you. Initially, keep training sessions short and where there will be minimal distractions even if it is just in your yard. A walk should be fast paced and not a stop and start exercise. The dog should not be investigating, sniffing or socializing on the walk. Walk to a destination and allow the dog some time at the destination to do those things.
I use a food and praise reward system. I use almost paper think pieces of hot dog as the oil from them coats your hand and keeps the smell on your hand. Let the dog smell the treat in your closed hand. This gives your dog motivation to be by your side. she should be happy to follow your hand around the yard. Keep your leash short, but without pressure on it. If the dog starts moving away, a correction toward you should be made. Give her a treat every once in a while initially so she understands walking by your side get her treats. Try to time it so it is before she gets distracted. If she starts to glance elsewhere, give a correction and tempt her with sight of the treat. When she is back to paying attention, reward her with the treat in a low calm "good boy". No excitement to your voice as you want her calm. Repeat when you think his attention is shifting. As she gets better at paying attention to you and your "smelly hand", make corrections giving more praise and less treats. Before you know it, your dog will be walking right next to you all the time, with or without treats. When you stop, praise your dog with your voice or a few pats to let your dog know how good she has done. You can train her to sit or lay down when you stop if you want as well. This helps prevent his trying to run off if you stop to talk to someone.
Once your dog is pretty much always walking at your side, you will want to make a correction any time she stops paying attention to you. For instance, they are looking at a cat in a yard, give a correction so they look at you. if she is busy looking ahead and hasn't glanced at you for awhile, give a correction and reverse your direction. Do not stop and wait for the dog, just a quick correction and reverse and walk. They learn to keep an eye on you as well as on what else is going on. Try an be confident during these training sessions. Try not to look down at your dog but more out of the corner of your eye. Act like you are paying attention to the scenery. It sounds strange, but it does work.
Once your dog is doing well in the yard, try adding a few distractions such as family in the yard, then progress to another dog around continuing to correct if she even looks like she is going to glance at the other dog. If you wait till she is already distracted, it is too late. You have to catch her before she focuses on the other animal or person. It is a lot of work and takes lots of practice but it does work.
This method should take care of your problem.
There is another method that is often used as well called BAT. You can read about this here:
What might also be helpful is to find a similar sized, laid back male dog around her age for her to play with. A labrador would be a good choice as they are pretty docile. Let her get used to him away from home and other dogs before allowing contact at either's home. If she gets along pretty good with him, you can start finding other dogs for her to interact with. If they don't interact pretty peacefully when they first meet, don't continue. The worst thing would be for her to attack another dog or have them attack her.
It usually takes a combination of techniques to combat dog on dog aggression so don't just try one at a time. Try multiple technique together. I hope this information is helpful to you. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have . If you do find this helpful, please take this opportunity to rate my answer positively so I am compensated for my time.