I imagine she majored in Engineering, both as a personal interest, and as an addition to her hero work repertoire. Being a Super puts you in all sorts of situations where engineering knowledge could be the difference between life and death; knowing how to fly planes, diffuse bombs, or find weaknesses in robots are all very valuable skills. (But regardless, I think it’s something she was naturally adept at and interested in anyway.)
Of course, with a STEM degree like that she would also have a guaranteed shot at lots of civilian jobs, if she wanted them. Even before Supers were forced to go underground, she wanted to have the safety net of backup career– just in case for whatever reason she couldn’t do hero work anymore.
It’s funny to think that despite her probably being a stronger candidate for a lot of high-paying jobs, Bob still ended up being the one working while she stayed home. I think it’s because he was really set on being a provider, because it gave him some sense of purpose. And Helen was happy to get to spend a lot of time with the kids, something a demanding job wouldn’t have allowed her to do.