Want to go to b-school in mid-30s but no clear job prospects

I've been reading a lot of threads on this forum and have posted a few questions. I'm in my mid-30s and want to get an MBA because I believe it'll help me transition into a new industry and possibly function. I have several years of management experience in nonprofit and an Ivy grad degree, and founded my own PR firm. But the only brand name I have on my resume besides by schools is my first job at a top 3 integrated oil & gas company.

I'll probably go into a PT or EMBA (I know, not looked kindly upon here) because of my circumstances but also because it seems nearly impossible getting into a top program at my age and profile. My goal would be to study strategy and/or finance: the former I have some experience in in my nonprofit work but not anywhere like most MBAs (e.g. MBB, Big 4); the latter is because I'm fascinated by investments and investing in companies and, frankly, have always enjoyed the idea of working in finance in some capacity (did PWM internships when I was in UG).

Ultimately, the goal of getting the MBA would be to have the skillset that's going to secure the highest level of income I can manage.

Here is my problem: every single one of the areas I've looked into on WSO (PE/HF/IB/AM/Consulting) makes it seem like it's damn near impossible to get into. I don't know if this is an exaggeration or of it this is what it is but it makes me wonder what the point of getting an MBA if I'm going to be unable to crack into any of the highest paying professions or any of the ones where I see myself.

Is it really that unheard of that a nontraditional MBA grad goes into one of the aforementioned areas without prior experience? Does school attended count for anything? How about academic performance? If I can prove my worth in my classes, will that count for anything? Are there any other post-PTMBA/EMBA paths worth considering that I'm currently not?

Any input/advice would be appreciated.