<human>: Give me the gist of the text in a nutshell

I'm 18, f, bisexual. I've been dating my best friend for over a year now and she is amazing and nice and understanding. I love her but I'm unsure about a lot of things; I can't really see us getting married or spending our lives together. She is the first and only person I've ever had a real relationship with, and I can't help but wonder whether I would be happier with someone my age(she is 23), or somebody more confident, or who I can see more often(we go to different schools and she will graduate this year.) I've become a much different person from when we first met, and now that I have the confidence to take on another relationship, I always find myself wondering what it would be like to be with someone else. 

Also... some of the reasons that I want to leave are also why I think I need to stay. She has social anxiety and I love spending time in big groups, so it's really hard for me to introduce her to my friends. She is also transgender(MtF), which I have helped her through for a long time, but sometimes the depression and gender dysphoria get really bad and hard to deal with(for both of us). I don't feel like I should be obligated to stay with her just to help, but also I can't leave her at a time when she needs so much support. Not sure what would be best to do in this situation: just stay with her through the uncertainty and complications, or break up and change everything around?
<bot>: My girlfriend and I have a fairly good relationship with few minor flaws. We love each other but I can't see myself spending my life with her. Should we stay together?