In this particular question, I'm interested in ASL, but also learning language in general.
I've read and heard warning against learning ASL from fellow students. Mainly because when you learn wrong sign, most of the times you will stick with the wrong form all of your life.
However, in a situation where you cannot, or have difficulty, to find a teacher, is it better to still learn from fellow student, or stick to online learning?
It is better to practice than to not practice at all. Failing to make any noticeable progress in language learning is a real risk.
As long as you are practicing with someone for whom ASL is an L2, then you both will speak a heavily English influenced ASL. This leads to a risk of fossilization, where you have habitual language mistakes you make all the time and it will be hard to change the habit later.
That said, the ASL community is very often bilingual English and ASL, so they are used to seeing English influenced ASL and will be able to recognize and understand "bad" ASL.
If you're aiming to be a professional interpreter, you might care more about the risks of fossilization and picking up bad "English"-like grammar.
So don't let the learning strategy of a professional interpreter derail a goal of basic functional skills.
