well,
I am overweight, have no beard and drink spirits & wine and the occasional cider. I wear what I like. I sing with my eyes closed to avoid distraction, as I am notoriously good at forgetting the words. I dont think I am a stereotypical folkie, and I know a lot of people who do look like you describe, it is probably because they are like minded people. To get accepted, it is better to learn some songs, and sing them well - and you will be asked to sing lots - whether you are wearing a wetsuit, naked or in full morris gear! It is to me a matter of ability that gets you accepted, not how you look. I wish you well, be yourself, and don't develop an over sized ego, that doesn't go down too well either!
Cheers, Lucy