Let's look at this together-
1) you're feeling guilty because you believe that you've missed on different opportunities in areas such as relationships, activities and work.
2) your family is not approving of your desire for the surgery.
Whose standards do you feel like you've not lived up to? The last 10 years are what they've been based on where you were in your life at that point (emotionally and otherwise) External circumstances also play a large role in how one's life turns out to be. Grieving over the past time as you realize is destructive. At all times,you go through transformations in your life - physical, psychological, emotional, spiritual, educational, professional, relational...
The goal through this journey in life is to be able to keep one's peace of mind while in the midst of changes. Impermanence is the one thing that is constant.
If you were not disappointed in some areas of your life or some things, you may have found something else to be upset about. It is human nature.
As far as the lack of support from your family, if this procedure is what you want to do, you should find a way to do it. If you have at least one good friend who can be there for you along the way, ask them to do it for you. Some insurance companies provide telephone wellness coaches as well and something for you to look into.
This is your life not theirs to live on your behalf by telling you how to live it.
Meditation is a good idea as long as you are trying to find peace in a constantly changing and hurtful life/society. You may like some of the writings of Roy Eugine Davis and possibly connect w/ a yoga/meditation group if one exists in your area.
The best approach may be cognitive behavioral therapy or any kind of mindful practice (meditation being one) Being aware of what you think, ruminate over, why and what you believe as a result, and in changing it takes practice.