Do it anyway, man.
I used to always do lolita themed outfits for cosplay at the anime cons. But about 6 years ago I stopped going because things were so bad and then I gained 100 pounds all of a sudden due to the extreme depression and had to hack off all my hair also due to depression/lack of care, so I haven't been able to go for all this time. I am 31 now and like... I really want to cosplay as Chii or do like a lolita Chii (from Chobits.) Idk... lolita is just so easy to do. But maybe I'll have to come up with something else. Because a thirty something year old cannot cosplay an innocent or even not so innocent seductive youngster who entices old pedophiles, can she? (And I definitely cannot do Faye Valentine from Cowboy Bebop because of loose skin.) What to do, what to do... to work so hard for so long and then realize I've gotten too old to meet all these goals I've literally almost died for.
There's a place at cons for every loli. (And fat male sailor scouts). One of my friends has been a thin loli, a morbidly obese loli, a young loli, an old loli and everywhere in between.
Unless you really don't want to. Then don't. But if it's what you really love, then go find a con with an older crowd base and cosplay your pants off. (DragonCon comes to mind if you're US based. I go every year. I'm super shy and don't really dress up but man... there are people of all sizes and shapes strutting their stuff and NO ONE GIVES A DAMN!).
Edit: And I have replied to a super old post. Apologies!!!
Reply still stands. Go to DragonCon. Hang out with us freaks. No one will notice how fat/skinny, young/old, cool/inept, scantily clad/covered you are.