I can't say that I've experienced this, but ALL my friends DUMPED me after my husband died, so............
Why don't you "nicely" ask her that if HER life is so grand, why is she trying to DENY you a grand life, by carping about your attempts to MAKE it grand? You're going to school to try to improve your chances of making life better -- so what's HER problem?
She's either jealous of the time you spend away from her, or jealous that you're going to pass her in the money-making. Whatever her problem, I'm not sure I'd like it.
Sounds like after all these years, you two should be able to talk heart-to-heart. If you're friends after 27 years, I would think you'd be able to straighten this out. You might give it a try.

It would be a shame to lose a friendship after all these years.
God bless and good luck! Hugs, Lee