Confused about Kitniyot and family background — need advice for Passover

Hi everyone, I’m hoping for some advice or clarity here.

My family is Jewish, but we’re not super religious. We’re originally from the former USSR, and after WWII, my great-grandma didn’t really pass down many traditions or things of the sort to protect my grandma and mom. Because of this, a lot of our customs are kind of unclear. I always thought we were Ashkenazi, since my family comes from Ukraine, but I know we’re a mix of different backgrounds (including Spain from way back).

Here’s the issue: I got into an argument with my mom about kitniyot. I thought we were Ashkenazi, so I figured we shouldn’t be eating things like rice, beans, corn, and buckwheat on Passover. But my mom said, “No, we always ate those growing up — we just avoided chametz.” She identifies as Ashkenazi, but it seems like we followed some sephardic customs, even though we technically aren’t.

My great-grandma was more religious, but she apparently only avoided chametz, not kitniyot. Now, I’m trying to learn more about Judaism and become more observant, but I’m still in high school and didn’t grow up with these practices. I don’t have many resources or recipes to go off of, and my family doesn’t really practice. It’s also hard to find decent food for Passover, so I’m just trying to figure out what’s okay to eat.

Is it okay to eat kitniyot if that’s what my family always did, even though we’re technically Ashkenazi? Would really appreciate any advice or thoughts on this!

Thanks in advance!