I think I might be interfering my younger cousin life too much and this puts a strain on our relationship

I have a younger cousin. We spent a lot of time together growing up and I care a lot about her.

She’s completing her bachelor’s degree this year in a university in my hometown. I’ve went there too.

She’s a bright kid, had great grades in school and was often getting prizes in city-wide competitions in multiple fields. However, since she’s enrolled in university she’s been putting less and less work towards education, instead spending a lot of time partying and stuff. She’s had many, many problems with professors because of that and she never had a job, relying instead on her parents & boyfriends for financial support

I think there are a few reasons for that. First, she’s a got a sweet taste of freedom after spending her childhood with somewhat conservative parents. Secondly, her new friends are not a great influence in my opinion. One of her besties has cheated on her boyfriend, the other one was messing around with her biology prof for like a year. I warned my cousin that it is in her interest to find friends that put more effort in education instead but she ignored me.

She’s also been having relationships? affairs? with guys that I found to be off-putting. Recently she’s broken off with a 29y old guy that works on campus which really made me uncomfortable because it felt quite obvious that he didn’t really care about her and just wanted to have fun with a pretty young girl. I have warned her about this beforehand but she screamed at me saying that it’s none of my business.

This week I’ve heard rumours of her hooking up with a lot of guys in town. I know that she’s already had a few STI/STD scares. she’s also asked for my help once to get a cervical dysplasia treatment in a secret from her parents.

I know for a fact that one of these guys is a huge douche who’s wife left him and took her daughter with her. He’s a creep who follows a lot of teenage girls on Instagram.

I’ve tried to tell about it to my cousin as cordially as possible, saying that she deserves better and maybe it’s time to look for a serious relationship with a good guy. I’ve also hinted at the fact that having a history of STIs at a such young age, as well as hooking up/dating with assholes is never a good look when trying to find a significant other, especially when we live in a conservative area & she fully expects her eventual husband to take full care of her, so she won’t even Have to pay for rent and food.

She was absolutely pissed at me, calling me a you-know-what shaming asshole and that such a situation will never happen because she’s not idiot to tell about her past to her husband. We haven’t spoken much since.

Is she right about overstepping my bounds? Probably. I just wish for her to be safe&happy. I hope I’m wrong and she will be fully able to put her past behind her.

TLDR: my cousin has been doing badly at University, instead spending a lot of time with people that I find to be unworthy of her time

Should I stop trying to give her any advice?