M20 in need of marriage advice bc F22 girlfriend shows patterns of flight risk

So my girlfriend (F22) and I have been together for almost two years, which I am very aware is not a long time in terms of a relationship. However, we went to high school together and have the same long time mutual friends and have known each other since we were in middle school. We are now separated by college (she commutes from home and I am 4 hours away). During the summers and breaks we live alone together in an apartment that we renovated from a family members large house and she comes to see me about every two to three weeks. So far our relationship has been great, the sex is mutually awesome, we have similar values, albeit there are minor differences in tastes and very niche topics. Where we are currently struggling is our long term future, we both are good on communicating and commitment but she is very fearful of her career and education getting in the way. She’s been struggling in school and has transferred colleges and is planning on transferring again. Of course I am supporting her how I can and though it would be emotionally straining would be accepting of her transferring to a school that is much further from me. She doesn’t know what she wants to be and cannot seem to maintain focus in a subject or believes it is too difficult for her to pass classes. I very much intend on marrying this girl and we’ve had the conversation several times and talked about kids and life together and are both excited to be together as husband and wife. We even jokingly went to a jeweler and browsed engagement rings (70% off sale for Black Friday :). Financially, I am supported by my close family, she is in part supported by her mother which is her only close family and sometimes struggles to make ends meet especially with school debt. I am hoping for a high paying job as an engineer and would love for her to be supported by me. My need of advice is when I’m ready to propose, likely within three years or less, I feel as though I will be putting more than my share of the relationship should she give up on her career interests, which seems likely. We’ve talked it through as best we can but I feel like an asshole every time. I try to support her “whatever you decide you should do it 100%” but she deflects. To the married or engaged men or women out there what should I do? I want to be committed but I feel she has to put in similar work for our future or at least not give up because I fear that trait may also come back in the form of leaving when the going gets tough in the relationship.

As a side note this fear was also brought on by a time I got black out drunk with her and ended up yomming in my sleep. It was scary for both of us, and she helped clean up while I showered , but instead of staying by my side and being there for me as I had been, keeping her hair back and being by her side in similar situations, she left me and slept at her moms. I’ve talked to her about this and she says she would do it again because she had to work and didn’t want to sleep on the couch. Maybe she’s in the right here but from my POV I would’ve stayed with her regardless of the circumstance.

She’s had some sexual trauma in the past and she’s worked with a therapist and had great success, but I fear in the long run there could be a pattern to her flight response. How could I go about talking to her and should this affect our long term relationship?

TL;DR

My girlfriend might be showing patterns of flight risk in her career and times when I needed her. I feel like I might be giving more than she is at times. How do I talk to her about this? Should it affect the choice of married commitment?