Should I Take Legal Action Against My Mom For Not Repaying Me 5,000$?

Location: New Mexico. I (18F) was granted a 2018 hyundai tuscon my sophomore year of high school as my first car, it originally belonged to my stepdads mother, but she eventually became too elderly to drive, so the title was transferred to my mom and stepdads name, and then given to me. I had jobs here and there throughout high school, but was not asked to pay for the car until i turned 18. I got a better paying job and was now an adult so me, mom, and stepdad made a verbal agreement that I could buy the car off them for 6,000$, paying 1,000$ a month. We all have a joint bank app with separate accounts, so my mom was able to transfer money from my account (500$ per biweekly paycheck). This went on for 5 months and i had payed 5,000$ at this point, when me and my mom got into a disagreement regarding the car. i wanted to move out, but she didn’t allow me to take the car with me until i had paid the full amount, although i was only 1,000$ away from the verbal agreement, i was mentally exhausted living at my moms and just said F the car and moved out. She claimed she would sell the car and give me all my money back, which did not happen, she instead gave it to my eldest sister (28F), now handing her the responsibility of paying me back. My older sister is not well off financially to say the least, she attempted to get a loan to pay me back the full amount which was denied, so she has resulted in paying me per paycheck, so far it has been 6 months and i’ve only received 300$ from my older sister, who is now registered owner of the car. I depise the fact that my mom just basically handed the car over and the responsibility of paying me back to someone else. Would I be able to take legal action against my mom even though the title is no longer in her name? Is that morally okay to sue my own mother? Should i just continue to let my financially unstable sister pay me back gradually?