It's good that you're so keen to learn and have clearly absorbed a lot from this forum but perhaps you need to empty your cup
Slow down and learn each stage properly before trying to jump to the next. It's the quickest route in the long run. The more solid each foundation, the easier the jump to the next level will be.
If you have good edge control you can get down anything (in a side slip) so stop worrying about the steeps and worry about the basics. Once you have good edge control, there's not much need to crash and hurt yourself. Be in control and use that as your platform to progressing.
I don't know how steep your area is but I bet it's not actually as steep as you think anyway. Give it a few days/weeks riding and it probably wont seem that steep anymore.
Focus on being balanced and completing nice tidy controlled basic turns that are controlled and not risking further injury.
You will also notice that it's becomes much less physical effort (strain on the legs) once you start to dial in your basic technique too.
And for whoever said it's all about confidence... personally I'd choose competence over confidence anyday. But the confidence will come naturally as you gain competence.
p.s. i'm also 37 and have learned within the last year or so.