Hi Klovesey,
I think in general, the best thing is to try to use what you're learning. It's ok to mess up, it's ok to look silly and feel stupid sometimes. If you shy away from that you'll slow your learning process way down. And I think it's very respectful that you're making an effort to learn your friends' language. The opposite of rude, really.
But you also said your signing is mostly guesses at this point? If that's really true, it might be more respectful to look at some of the stuff you're guessing at and try to learn about it, so that you're not guessing so much. Do you have access to classes? How have you been learning?
Same thing about sloppiness. If you just mean that you're not yet fluent, that you're awkward because you're a beginner, I think most Deaf people understand that and won't hold it against you. If you mean that your execution is actually sloppy, I'd try to clean that up. Practice in front of a mirror, and try to make your signs as cleanly as you can. The way you practice will have a big effect on the way you sign.
If you're worried about being rude, I think you just have to imagine yourself in the Deaf person's situation. I've seen people who knew a tiny bit of signing try to interrupt a fluent ASL conversation to excruciatingly sign "Me name [fingerspelling]". So that's pretty awkward, rude, etc. On the other hand, if you're having an interaction with people who want to interact with you, and you're making an effort to sign rather than just write/text/act it out etc., I think that can be great for everyone.
Good luck!
