I thought of another build-on for you that is mighty important.One of the most important things is training the body to operate in free space(our lovely world with gravity, but a lot of instability).Ideally in your case, you should aim to progress to exercises that are considered functional. Functional in training sense is something that can transfer or be replicated into the real world. For example, basketball players squatting and overhead pressing because when they jump straight up to block a shot, it literally is the same combinations of movements.So while you aren't playing basketball, you are walking and stepping up and over instable objects. So you want to eventually progress to different stanced lower body exercises, even single leg because balance and stability must be trained. For the upper body there is always a time where people may need to support themselves with 1 hand while leaning, push themselves off the ground, carry unstable or unbalanced objects, reaching with outstretched arms with tools in strange positions(which all translates to core activation) etc... so when you are doing your exercises, you should and will want to aim to get into things that most replicate movement in free space. This is why gyms include free weights in place of just machines and this is why the most highly skilled sportsmen and athletes use free weights in a majority of their training unless its a sport specific machine.
I thought of even more, now that you have had a chance to process all the other info - and believe me I know its a ton.I thought of this when talking to my own mother who around your age. You need to be working and balance and stability as a part of your exercise routine.By this I mean incorporating(in a safe manner) exercises that force your body to upregulate your body's sense of spatial awareness, meaning that when your knee or hip or ankle(any joint at all) is in a certain position or the body is at a certain position, the reflex system realizes this and has muscles ready to fire and control the body.We see this need in elderly populations where the people have been so sedentary for so long and haven't "trained" these functions that the body simply can't control itself leaving them open to falling and other injuries related - in many cases strength and balance training would have prevented a lot of this.So the easiest ways to do this are doing the single leg exercises and "split stance" exercises like working the stairclimbing, lunging, doing the exercises on carpet in barefoot(versus the stable wood floor with sneakers on), doing single leg balance while doing chores, and progressing to a point where you can stand on one leg for a good period of time, even making it more unstable by placing folded towels underneath the food, pillows, but always making sure you are controlling and "recovering" from the instability even though the ankle knee and hip musculature will be firing to keep you stable. Even doing your upper body exercises like the overhead can pressing, tricep extension, rowing, bicep exercises for the arms, doing them on 1 foot will help tremendously because remember: those arms are levers and they are influencing the lower body to stabilize through the core.You will find that adding this in to your workouts at home, day to day things will improve for example you may only get 15 seconds even just standing on one foot, but the next day you may be able to stand for 20 or 30 seconds - the body responds quite fast to low level instability training.The point of all this is to add them because you will always be at an advantage to someone who doesn't do this type of training, more importantly you won't run into the risks as you get older of having poor balance and strength thus keeping you safer.