So I want to take some classes at the nearby community college this summer, but I am unsure of what to do about my name, which has not been legally changed yet. Someone suggested to me that I sign up with my initials. But when I looked at the registration form there's a space for "legal first name" and "legal last name" only, and nothing about what you prefer to be called or anything. Does anyone know if your initials count as a legal first name? There's also a space for gender which I don't know what to do about. I'd rather not be out there at all, but I'm not sure that's possible.

If it specifically says "legal first/last name" then I'm pretty sure you have to put your full, legal name.  I don't think there's anything illegal about putting male down for gender, though, or seeing if you can get away with leaving it blank.  Maybe you can put your prefered name as your middle name and then e-mail all your professors before the semester starts and tell them to call you that.

I don't know if this is a viable option where you live, but I think calling the school or making an appointment to see the principal/head of student services/whatever about it is worth looking into, rather than filling out the form. Just explain to them that due to your circumstances, the form doesn't work for you, and could you be put down in the role as 'blah' name with 'blah/undefined' gender. This worked great for me at my college, when asked to fill in a form I calmly explained (without going into anything trans related) that even though my name was 'blah' I wished to be known as 'blah'. Most people will understand, and it's not a big issue for a school to fix, so I don't see why aproaching them about it would cause any harm.

Always worth a try

Ask if they use the latest Banner system. It's a computer program used by colleges to register students. If they have the most recent version of the program there's a place to mark a preferred name and pronoun.

This college uses the banner system and has info about their system here

The banner system isn't a great thing though. I did that, thought I had covered my bases, turns out professors get both names and don't look at prefered names. I got outed in class one day by a prof. Anyhow.. I'd suggest you go in and tell the office and ask to talk with someone higher up then a sexretary and tell them what is up. I did that and talked to the vice president of the Uni, and they changed all my info in the system to the appropriate stuff and essentially registered a person that didn't legally exist. They did it because it's considered some kind of risk to me if they don't change it.. people finding out I'm trans by being outed by profs and whatnot. It was fine though because I got my real info changed before I graduated.