Anyone ever tried "relearning" math as an adult?

[HeartachesNhangovers]

15. Like Khan, Open Stax College has free e-textbooks

for self-learning: https://openstax.org/subjects/math

I don't think your problem - if you are like most people - is age; it's motivation. I went to Catholic elementary and high schools and didn't have any "advanced" math or science, even though I got through an engineering program in 4 years - although it wasn't easy for me. After I retired, I decided to brush up in order to maybe do some volunteer tutoring. "Brushing up" on math is time-consuming and difficult. But if someone is determined to do it, it is possible for anyone of normal intelligence.

If you just want to get through calculus and maybe statistics, any community college should have the classes you need.