I must agree that it is both cute and quirky. I like it! I bet you were super disappointed when she didn’t react the way you expected. I’ve run across many parents who are supportive of LGBT people in general but not when it is THEIR child. I don’t get it but it’s just a fact. (It’s okay for the neighbor to have a lesbian daughter but US?!)
Wow, she knows you’re not a lesbian? I don’t know anyone with that superpower. You must tell me where she came up with the age “22”? Perhaps she is supporting you financially until then? Perhaps she was just overreacting and will realize with time that you can’t dictate someone else’s sexual orientation. I wonder what she would say if you told her that SHE was not heterosexual (not suggesting that but you know, I can’t help wondering). When she was 16, did she know she liked boys and wanted to date boys? What if she were forced to live as a lesbian and only date girls from 16 to 22? (I think I would ask her that one).
My only advice for her becoming more comfortable is education and support. Education (see the books and web sites I’ve listed under my info) and support so she sees that parents survive having queer kids— what is important is that SHE help YOU to survive BEING a queer kid! She will get that message if she attends a support group such as PFLAG (see PFLAG.org for info, educational support, and to find a chapter near you).
You may have to be the mature one for now and gather the reading material and look for a support group for her. If it comes down to it- you might have to figure out a way to put yourself though college and support yourself after you turn 18 in order to be your authentic self. You can tell her that is an option for you but you’d rather be with her and have her love and emotional support. ♡