Hey man, congrats on starting up vocals.
First of all, I don't mean to sound condescending but you should make sure you know exactly what you're doing. Make sure you're at least 16 and make sure you feel NO PAIN AT ALL when you're screaming. If you feel pain you're doing it wrong and you're going to seriously damage your throat.
Yeah, the sm58 is what I have. I feel like I should have saved up and bought a beta but whatever, I think that's a good decision for a first mic.
As for people saying to not record yourself, I think that recording yourself is actually a very very good idea. Sometimes what we think we sound like and what we actually sound like is very, very different. Record yourself whenever you practice, I would say. That way you can track yourself, listen to it, and find out what you need the most work on. Then, the next time you practice, you can go about fixing it.
Also, I would try and practice for at least 10-15 minutes everyday. When I first started out I was living at home and it was hard to get alone in the house to practice, so I ended up practicing about one or two songs once a month. That really hurt my development. Even if you're just singing, practicing any kind of vocals at least once a day is going to help out A LOT.
Good luck, man! Stay metal!