I have been saving ~60% of my income so far (almost all of which is going towards student loans
Clarification: If you're using that 60% to pay back student loans, you're not saving it. You're using it to repay money you've already spent. Yes, that's admirable, and it's not the same as spending it all on a cool motorcycle and going out to bars ... but neither is it saving.
She is very career oriented, as am I, and we're both kind of stubborn, so this new development has caused some friction.
The "stubborn" part grabs me. It gives me the impression that you both want the other to "give in" and say, "Okay, you rule the relationship. I'll do what you want." If you want this relationship to work, BOTH of you have to give that up and decide upon SHARED GOALS and HOW to reach them.
I really think that's the crux of your issue: You and your girlfriend lack shared goals. I think you both need to decide what you want your lives to look like in 10 years, 20 years, 50 years ... and see whether you want the same things. If you see yourself working hard for a short time, then settling into a little homestead and relaxing, while she imagines herself living near a big university and devoting herself to her work until she's 60ish, you have a big discrepancy.
Right now you're at the point you have to make decisions. I suggest you float the idea to her that next time you're together, you do some serious talking about your adult goals ... and make decisions based upon how that goes.
Two careers (not just jobs, but careers) in one family can be tough. Where to live, how to take care of the kids, etc. doesn't always fall into place easily, and the only way to deal with it is to have a clear-cut vision of what you want for your family ... and when a question arises, ask which option fits into your shared long-term goals.
For what it's worth, I do not buy into the idea of soulmates or "love of my life". I don't buy into the idea that one person exists who is absolutely perfect for you, and no one else would work. I think any number of potential partners exist with whom you could be happy -- though perhaps happy in different ways, since your life will progress differently based upon which partner you choose. You have to decide whether this girl is it for you or not.
For what it's worth, I dated a guy for three years in college, and I was
sure I'd marry him. We got along well and were kind of the "it couple" in our circle of friends. However, when we were seniors and were preparing to leave college and move into the world of work, I realized that our goals were incompatible. No, he and I weren't incompatible --
it was our goals. The biggest issue was that he didn't want children, but where to live and how to spend money were also big concerns. Our differences had nothing to do with careers; rather, they were more lifestyle based. I knew we'd always be fighting over a few fundamental goals, so I ended it. He never understood why, and I'm sorry for that ... but I don't regret the decision to leave him.
As for couples not fighting, my husband and I rarely ever fight -- I don't know that that's good or bad. When we disagree about something, we tend to discuss it and decide what's best for the family unit, and we do it. We're coming up on our 25 year anniversary, so something's gone right.
I have seen so many young people (I work with college students) who have tried so hard to shoehorn their lives into a small space to fit the life path of a partner who didn't share their goals.
Yes, I remember that when I was a senior in college, trying to decide whether to remain in the above-mentioned relationship, one of my big concerns was, "I've put three years into this relationship! It's working well! How can I be thinking of ending it?" At that point, three years seemed like so much time. I should've been thinking more about the 70-80 years I had left to be on this planet!
As I said above, he and I lacked shared goals for the future. It was better to cut it off and "throw away" the three years than to try to force one another to live the way we wanted to live.