Let's see.
tomorrow's Thursday - call her and tell her that your friends have planned this guy's night birthday bash and that you would like to spend time with her for your birthday (yadha yadha) on Thursday (so you can have some time alone - without the "guys") - if Thurs doesn't work try for Sun (you'll be worthless on Saturday don't bother). You have to tell her ASAP in case she had made plans for your b-day or was going to make them.
2 months - that's a pretty new thing and her response to the above will tell you A LOT about her maturity level and neediness level. People who are never ever single and go from relationship to relationship (no not sexual relationships) tend to be needy.