I have no idea how much I can lift.

For this, try and push firefighting school back (I'm assuming you meant this September as in next month). It'll be easier for you to assess what you can lift (and do in general), train for a while, and then go try out. You don't want to head to firefighting school and juggle physical preparedness, potential body image stuff, and being new to the process of getting stronger/in shape.

it feels sort of wrong coming on a subreddit full of female lifters and saying I don't want to look muscular but it's just a personal thing. I don't think it would be a good look for me.

You're not the first to express this concern on xxfitness. So you don't have to worry about. Plus the subreddit in general tries to let everyone have their goals and preferences intact.

(if this comment was helpful so far, you can stop reading here)

I just don't want to look like a female body builder or something.

You cannot possibly look like a female bodybuilder without literal drugs, not even if you want it and try for it without drugs. I'm not joking - and people that want to invoke "bulky" can please refer to my comments/that one post I made about being fat and thinking flabceps are biceps. Is it possible to seem one's body is getting out of control? Yes. Is it likely people forgot women build muscle at 0.5 - 1 lb a month if they bust ass and god wills it leading to people overestimating how big their muscles are? Yes. The "or something" concerns me because I don't know what to say if "or something" means Madonna's arms or Jessica Biel in Blade 3 (in any case these two examples are too lean for people's tastes. But it seems people equate lean with "huge muscles" because of definition regardless of the actual size)

And people can get strong without getting big or very visibly muscular bodybuilding style. You can search r/xxfitness, r/powerlifting, on reddit for everyday women squatting, deadlifting anywhere from 200 to near 400 lb of various sizes. Here's one that's active on xxfitness, she competes at 125 lb. You can even look for videos of olympic weightlifting and powerlifting competitions in weight classes around your weight to see for yourself.