I am realizing that I might have messed up 2017 taxes. I thought I E-Filed them but I am starting to realize that I accidentally selected file by mail.. What do I do now?

If you're receiving a refund, you're not in any trouble. Go ahead and file so you can get the money that's yours! (Unfortunately, you won't get any interest on the money you let the government keep all this time, but at least your stress about it can go away!)

Awesome, so do I just print and file that way?

I did the same thing how can I e-file if I selected mail on accident.

You cannot e-file a 2017 return.  E-filing is permanently closed for 2017.  But you can print, sign and mail it.