Full-Time Student needing some help

I’m in college full time, my parents don’t pay for my education, I paid for my own car in cash and insurance, and now i’m looking for a new car because while I was away at school my car was at home and got infested with ants, mold, and other issues because of its age. I would have to finance a new car because I don’t want the unreliability of a cash car that I previously had or cash outright to buy a nice one. I found a car within my budget but i need a co-signer due to being a student and the type of work I do is not stable income (I do research and will be doing a paid internship at a lab this summer). I told my mom that I would need a co-signer and she said to ask my dad but she didn’t think it was the right thing to do by financing a used car (it is 10 years old). I’m paying for everything and did the price breakdowns, I plan to get a regular job after my internship to keep during school but i don’t know anymore to ask my dad to co-sign or give up on the idea.