I'm an 18 year old girl so allow me to shed some light on the situation.
I was in the same boat as you. I have 4 brothers and they were always allowed to do more than me. They told me it's because I'm a girl and I didn't think that was a good answer but as I get older, I will do the same to my daughter one day.
Girls are not safe. Especially young girls. Kidnappings and rapes happen everyday. This is reality. They are trying to protect you. No way in hell would I let you walk by yourself to work. I don't care where you live. By the way, part time is perfect for your age. You don't need more because school is priority.
Now I will say that the whole sleepover thing is a little much but there could have also been something that happened to your mother at a sleepover that she is trying to protect you from.
Also, not to be rude but the way you are handling this does not show maturity and if you are not mature, they will not trust you. Anybody who thinks they can "do whatever they want" when they turn 18 is just silly. You live under their roof and you follow their rules. They will lighten up on some things but if something is not allowed in the house, that will not change.
You don't have to believe it. You can think it's dumb. You can curse them up and down but one day when or if you have kids of your own you will understand.
Be thankful. Be thankful your parents care enough about your well being to keep you safe. Many are not so lucky. Many have parents who don't give one care in the world about what happens to them. Your parents love you and they are just trying to keep you safe. Be thankful.
An option you could discuss with them is some compromises. Have an honest and calm discussion with them about how you feel. Do not yell. Do not demand. Find some compromises such as maybe you could invite friends over for a sleepover. You can also ask your parents for some letting up in going out. You can come up with compromises such as no going out later than the decided time, you have to text when you get there, etc.
You are not in control. They are so if they say no, just suck it up until you can pay for yourself to move out which is years away.