Lifelong masking?

Hello, I'm in my early 20's and just recently realized that I might be autistic or some other "variety" of neurodivergent. I have a lot of questions about this –– part of me is trying to convince myself that I'm faking it. My whole life I have been treated as and expected to act like a neurotypical person and I think I've gotten a little too good at it, to the point where even I am doubting myself. I am able to pass as neurotypical, if I can get into a routine I can be fairly successful. However, recently I've been feeling extremely burned out and my difficulty with social interactions (relationships, both platonic and romantic, are something I've struggled with my entire life) is reaching a fever pitch. I know this probably doesn't make a whole lot of sense, especially not without knowing me or my whole story, but if anyone has any experience with diagnosis as an adult or any type of situation where others doubt that you are in fact neurodivergent I would love to hear your stories...