There are advantages to starting older, cos for one, you're more focused about achieving your goals. Its not as if you're forced to learn it, and you have to motivate yourself, which may sometimes encourage improvement.
Not all of us here are born super-dexterous, more often than not it comes out of constant practice and hard work. Finger exercises and proper technique will carry you a long way. Speed should not be your benchmark at least for now, but accurate fingering/picking and good timing. There are numerous threads on how to do this, so do a search.
Btw, I don't think its that embarassing la, more often than not younger kids look up to older chaps like us, whether or not u have skill or not. I guess most of us still respect elders la. But I agree that private tuition might be better if you intend to pickup faster.
It's never too old to learn something new.
Hmm 20 plus not old? True la, but i dunno why, I walk around in shopping centre after awhile sure have to find somewhere to sit. Old man la. haha :wink: