Scared while leveling up

Scared about levelling up.

I'm being trained for a very mathy position soon at my job, they need building materials engineers and they referred me because I'm smart and I cope with change well, the department is growing and they've already accepted me after three interviews.

I feel awkward because I technically lied about having a small degree to get the job (I was close to getting the degree but prioritized leaving abusers and didn't have a car at the time.)

I reapplied for a fully online college degree (environmental biology) where each class on average will be 15 hours per week, I'm waiting for everything to process on that.

Each class is 990, one class per term for 6 terms per year (one term equalling 8 weeks.)

I have credit card debt from car repairs / an important surgery (about 11k)

I make 46k a year after taxes.

Rent is about 1k

Random purchases (food / items) 500 a month.

I just started this job maybe a month and a half ago and I have nightmares that they're going to catch on to the degree thing, I'm really trying my best and trying to get past that classism barrier that I always seem to face and honestly they love me but still I'm terrified. It's probably because my previous workplace was so toxic I feel like I'm on "personhood guard duty.", I don't like lying to people but every guy I've met lies about degrees and experience all the time and they always get the job.

The training period for the new department (I was told) will be extensive , slow and hybrid because the work is so important and I can't make mistakes so they're pretty patient about the training.

I just want to make sure I'm making all the right moves and I'm not putting too much on my plate or trying to reach some crazy goal.

I'm scared of everything crashing down, I'm scared of them calling my old toxic boss and I'm scared about them finding out I don't have a full college degree even though I'm already in the company and on their payroll. I'm just really paranoid this is all going to fall apart and I'll be poor again working retail.