Big thing is to never give and up and stay creative.
Perhaps your mom is unwilling to drive you to a gay event, so part way may be a solution? Get you to public transportation and then you get the last nine yards without any discomfort on her part about going to a gay event.
Perhaps you can contact the event and ask for transportation suggestions. If it is a fund raiser then it is likely someone at an event for helping people may show and interest to help support you in some small way. Heck, you could -or rather should- offer to help cover gas, pass out raffle tickets, whatever to contribute in exchange for getting a lift. Offering to help is a great way to feel empowered. Maybe make new friends...
Use this internet thinggie to help yourself resolve your issues. There's a lot of crap on the internet, but there's a lot of good stuff too.
Enjoy your first gay event when it happens. And enjoy the second, and third. But, keep in mind though what a great gay poet once wrote as a one line poem in a book of poems:
"After an all night of going around to gay bars, I came home and said to myself...."Art."