AITA for telling my sister her dream is unrealistic?

Okay. I do think I need to give a disclaimer here that we live in a country where education is relatively cheap for a middle class family (which we are).

My (24F) sister (20F) is lovely, but she’s always been too ambitious. She has this crazy idea where she just wants to keep getting degrees in different fields throughout her life. I guess she’s like this because our dad always says that “no one can take knowledge from you” but when he said that it was for us to pay attention in High School, not to stay in college forever. She is finishing her Technology degree this year and she already wants to get into Accounting next year.

We were talking about the future and she brought up again the topic that it would be a dream to be highly educated and stuff. I decided that it was time for me to be a good big sister and told her sincerely that though it was a cute dream, she should be realistic and accept that it is probably not going to happen. It is time to grow up and accept that if she wants to be somebody in life she will at some point have to prioritize her career, and she can’t freeze herself at 20 forever for it to be feasible for her to always be studying. She got kind of sad and told me that I didn’t have to be so harsh about it and that she thought it was perfectly realistic. I said that she could do whatever she wanted but would come crawling back when she realized that she was wasting all of her money chasing an impossible dream.

Now things have been tense. She talks to me but never about her plans or things she likes. I kind of wish I never said anything, but I do think I’m right. I am worried that she will waste her young years on a passion for studying she will probably no longer have in 5 years. She is an intern at a good company and instead of working hard to get hired, she just spends all her free time studying. My parents think I was too harsh and that our place as her family is to stand by her whether her dreams work out or not. AITA?