It’s good that you’ve come to that realization, it’s why guys constantly are warning younger folks to wait until they’re older. Stick around here, and tell your stories to other 20 year olds who post here wanting to start. Sadly, most don’t listen.
I don’t know a ton about AAS, or the science behind everything, the guys above are far more knowledgeable. I just know people personally who have done stupider, and recovered, so I think you will be okay (unless you have some other medical issues).
Run the Nolva, if you’re really worried stretch it out like Iron said with the two weeks at 10mg at the end. Then wait a few months, see how you feel, AND GET BLOOD WORK DONE. Even if you feel okay, you may doubt your recovery, thus mentally making you feel worse. Seeing the numbers, seeing that you are good with proof from bloodwork, will remove those doubts.