Hurray!!! Keep going and soon you'll be rocking it. Really. Personally I think there's no greater satisfaction than seeing some skinny gal be amazed by a fat chick's fitness when you keep going and they can't.
Last night I did over an hour's worth of hard-core fitness with my club's women's rugby team. Yes, I struggled with 46th-50th leg lift. (!!!!) But I can remember a time when I couldn't do three. Yes, I flagged a bit on some of the speed drills. But I am one of the heaviest gals there (the heaviest?) And then there were some that I actually excelled at (strength based) while those fast, skinny backs were struggling. :-) And because it's a team, the fast skinny back who was partnered with me helped my through those murderous lateral leg lifts.