Yes of course you have a chance. Be confident and ask her out. She already sees you as funny so add it to with your confidence. I wouldn't suggest the movies, you know just in case you were thinking that. Every first date location is going to be cliche and movies seems to always top that list, but since you don't know much about her, go somewhere where you can talk, not where things are virtually exploding in your face. Talk to her and see if you even share the same interests.

If she's at all decent, and it sounds like she is, your size won't be an issue. There's already evidence that she focuses on personality since she said you're funny. Don't think that all people judge based on looks. I see gorgeous girls dating larger guys all the time at school. It's cute, and also reassuring - not everyone is shallow enough to not date a guy because he is "larger." Don't let it take away from your confidence.

theres always a chance my good sir. just a matter of you taking the opportunity to capitalize on those chances. that shes complimenting your humor is a good start, just dont go thinking of bf/gf to quickly haha

id say the best thing to do is ask her out for something to eat one day, best place to know her outside the group and you get the maximun to capitalize on your humor (see it all comes back around) and if things go good, then you guys can probably schedule something for a later date and continue to know her better

Woodz did point out something important there. Just as you are shy and not sure what to say to her, she's probably feeling the same way toward you. Girls have a tendency to compliment certain traits when they like you and don't know what else to say. It's just a not-so-covert covert way of saying that they are tentatively interested in you. This doesn't mean go in with all guns blazing, it just means that the chance is very good that she may be interested in you too.