I once went through this process with a friend of mine who was TOTALLY sure that they’d backed everything up. We double checked with each other 20 times before hitting “format”.
Except they had forgotten a folder full of photos. They lost photos of one of the most important trips of their life 
I felt terrible for them and even guilty (even though it wasn’t my fault!)
Ah man that’s a real bummer.
I will definitely keep that in mind.
Thanks @tengig and @LyingDalai for the back-up advice.
I know it should be mandatory but when in a hurry to get up and running it’s very easy to overlook/forget.
If it were me I’d actually format the drive and do a clean install with latest os for a fresh start…
But I don’t recommend it if it seems in anyway intimidating… Must be sure to know what your doing…
Thanks. I probably should of as that would of optimized it the best. But it’s already installing.
Would I have to make a bootable flash os if I were to do that? (just for future references)
I have did a bootable flash drive install before but that was because there was some log in error and was sent the bootable flash. So I’m somewhat familiar in that aspect.
You need 10.13 at least. 10.14 is Not available for 2011ish Macs. If Safari is Not working try Chrome or Firefox.
Apple stopped with 10.14 Mojave the support for Macs from 2011. My MacBook early 2011 cant be upgraded anymore either. He must use an alternative Browser to Safari which is new. And he must Upgrade Java too.
Apple should still provide a Download Link for 10.13. Here is for the German Version: https://support.apple.com/kb/DL1954?locale=de_DE