Well done!
You deserve your success.
My story is similar to yours, in that I had meagre school certificates and I paid for a slow, 'modular' course (but it wasn't called that in the 1970s). The main difference was that I spent quite a while instructing and doing classic GA jobs like air survey, air taxi and light exec-jet charters. That route to an airline doesn't seem to be as possible these days, which is a pity as I believe it teaches one a lot of things that MCC and JOC can't replicate.
44 years after my first solo, I finally made it into the LHS of a 'major', doing long-haul. I have enjoyed every step along the way.
Yours is an inspiring story and will hopefully encourage others who start off with less than ideal academic qualifications.
Again, well done!