[Daring Scylla]

this is going to sound awful but normally I don't think online/long-distance relationships are a good idea to work out
HOWEVER
you aren't going to know that until you meet him, and maybe you can work this angle with your mom
I can't tell from your post whether you've met him in person or not, but two years is a LONG TIME to stay committed in an online relationship so there's something working for you
if all else fails, don't tell your mom. let him come pick you up and when she calls asking where you are then tell her when she can't do anything. it's your life, not hers. if she wants to remain willfully blind of something you cherish then she's not being a very good mum