Could i sue my sister?

I am currently 18, and i had 1,500 dollars of college savings i had saved from working during high school being held by my mother. She gave it to my sister to hold for me since she couldn't or didn't want to anymore and i said okay. I then found out my sister spent the entire amount towards a new car she bought to make the payments lower, she now has no way of paying me back and i start college soon at byu, she says i cant charge her interest and there's no way she can pay me back for a long time because the car was out of her price range and she is broke. do i have legal rights here, nothing was really in writing but my whole family knows the whole situation and im pretty pissed at her.