There isn't a fix for feeling like this, Jess. It's not something that you can go back and change. These feelings are going to come if you let them because for us it is a very real sense of part of a life denied us.
However, the key part of that is the words "if you let them". Sometimes it's all a matter of perspective. A matter of the way you view your life. Sometimes I wonder how much do we actually think about how important our gender was to us in the things we have done, other than when we think of all the things we wished we had done. A person we wished we had been.
Perhaps one way to look at it is to think of all the things you've done in your life that you're proud of. All the souls you've touched, all the good you've done in the world. All the little things that make you smile when you remember them. And doing that, keep in mind that you're still that person you were before. You're transitioning now to become yourself externally, but you were always yourself internally - even if that's buried under layers of denial, repression, guilt, no matter what it was. In that sense, everything you've done in your life has been done by a beautiful woman. So you didn't have the same experiences as other women... that's fair enough. But many women don't have the same experience as other women.
Not every woman has had the opportunity to save a life. Not every woman has had the opportunity to make a lasting difference in the world for someone, or many people in your case. There are things you didn't have, sweetie, but there are also things you did have. You had the desire to want to make a difference. You had the empathy, and the compassion to want to help. The presence of mind to know what to do in a tight spot, to be relied on. Trusted. And maybe those aren't things related so much to gender, but they're things that make you someone very special. And someone who, I think, quite a few women would wish they could have done what you've done in your life.
Maybe you didn't grow up being socialised as a girl, or going through puberty as one. But you're doing that now. It's never too late to make up for things like that, sweetie. To reclaim what was lost to you. You are NOT old. Not even close. You have many, MANY more years ahead of you to make new memories, to make your life exactly the way you want it rather than being forced into situations because you don't know any better or believe it's what you're supposed to do.
Jess, your life has given you one very very important thing, sweetie. Self-determination. That, believe it or not, is something that quite a few people would give anything for. The ability to know yourself. To know who you are and what you want. Take that. Use it. Be the woman you always wished you could have been, and inside always were.
Each life is unique. Billions of beautiful flowers in the garden of life. Some open at dusk, some open at dawn, all are beautiful and all take in the energy of the world to be able to function, all bare their innermost petals to the outside. Show your true colours, Jess. Because trust me, they're strikingly beautiful.
*extra big hug and warm smile*