I got a seasonal job...

I’m 19 years old I have a 11 month old son and a boyfriend his dad. We live with my parents and get everything free. I started going to school in August and it ends in late November I go Tuesday and Thursday. My boyfriend works 8+ with my dad in construction in Los Angeles ca right now he’s making about $350 a week but he recently moved up to making $600. I went on indeed to apply for jobs for fun and stuff. WELL... UPS is about to hire me in the 2nd stage and I set up Direct deposit with them. My mom isn’t to happy about it and she’s fine with it now. My boyfriend said it was OKAY for me to get a job AND NOW he says it’s not a good time. That’s it’s unnecessary and that I need to be a parent to our baby. I want a job so my mom stops buying my son clothes and stuff. I don’t want to have to ask my mom to get my son clothes because my boyfriend doesn’t have enough money or makes me feel bad about asking for money. I would be working from 2am-6am so when our is asleep.