Friend makes petty comments about my financial situation

I'm frustrated with a friend and would appreciate some advice.
1. I feel like she's not making the most of her potential, but that's more her issue.
2. She assumes I'm more financially privileged than I really am, and therefore ignorant, and that’s what bothers me.
We both attend a state school where a lot of students come from lower-income backgrounds. I do okay—my parents went to university and smart with money, but we’re not rich. I don't have expensive stuff, we live in a terraced house, but my family prioritizes things like a good laptop or car, so people sometimes assume we're wealthier than we are and, therefore stuck up.
My friend "Olivia" has similar goals to me academically, has a similar-ish financial situation and defended me when others thought I was stuck-up. Important to note that Olivia has always enjoyed displaying the fact that she has expensive tastes. For example, she was talking about the £200 shoes she had bought, and I said I could never imagine buying, let alone afford to get, £200 shoes, whilst insists how necessary they are for her. She works as a babysitter, while I don’t have a job because I’m focused on school, and finding work as a teen in London is hard.
She often schedules babysitting shifts during school hours, during our frees which affects her grades. Some of her commitments, like her EPQ meetings, are now taking place during her frees, so I suggested that she stop booking shifts during her frees as we're in year 13 now and she has high aspirations. When I suggested this , she made the snarky comment "Not everyone can rely on their parents’ money." This felt unfair since she's never acted like her family struggles financially before and it felt like a personal dig at me.
Am I overreacting, or was her comment out of line? What should I do?

I did talk to her! This is the message I sent: i don’t know why but you said today about “not everyone can just rely on both their parents’ money” upset me. i’m going to stop with your suggestions about you should do with your work, it’s your life, but it just felt like a personal dig at me when i was just trying to make what i thought was a reasonable suggestion to a complaint you’ve brought to me multiple times. And I'm sorry if I misinterpretted why you have this job.
She replied with: understood. I'm sorry you felt that way by my comment.
But I still feel uneasy, because like you hint at, seems like she holds a bit of bitterness/resentment/prejudice that I never really expected. The apology didn't seem genuine and she didn't even explain where she was coming from, so in my eyes she just seems to be unfailry playing the poor matyr when she has a bunch of expensive things and always tries to play off as though she's middle-class. Half-term is next week so I think I'm just going to take the time to stay silent and cool off because this has been a consistent issue all term, but I don't want to get so upset that it ends our friendship.
Thanks for the advice x

I'm frustrated with a friend and would appreciate some advice.
1. I feel like she's not making the most of her potential, but that's more her issue.
2. She assumes I'm more financially privileged than I really am, and therefore ignorant, and that’s what bothers me.
We both attend a state school where a lot of students come from lower-income backgrounds. I do okay—my parents went to university and smart with money, but we’re not rich. I don't have expensive stuff, we live in a terraced house, but my family prioritizes things like a good laptop or car, so people sometimes assume we're wealthier than we are and, therefore stuck up.
My friend "Olivia" has similar goals to me academically, has a similar-ish financial situation and defended me when others thought I was stuck-up. Important to note that Olivia has always enjoyed displaying the fact that she has expensive tastes. For example, she was talking about the £200 shoes she had bought, and I said I could never imagine buying, let alone afford to get, £200 shoes, whilst insists how necessary they are for her. She works as a babysitter, while I don’t have a job because I’m focused on school, and finding work as a teen in London is hard.
She often schedules babysitting shifts during school hours, during our frees which affects her grades. Some of her commitments, like her EPQ meetings, are now taking place during her frees, so I suggested that she stop booking shifts during her frees as we're in year 13 now and she has high aspirations. When I suggested this , she made the snarky comment "Not everyone can rely on their parents’ money." This felt unfair since she's never acted like her family struggles financially before and it felt like a personal dig at me.
Am I overreacting, or was her comment out of line? What should I do?