You're going to hear from a lot of people who did these awhile ago. The physics have changed. There are several tests where the demonstration is complete BS IMO. I recall one where it was a BMW on some off camber corners and the speed the demonstration used was flat out not possible. Most of the demos are fine, I probably counted 3 or so in all the license tests that were so off that it was notable and easy to identify.
Having said that, I recently golded all the license tests so it is still possible to do, even if not the way they demo it. PD is notorious for breaking the license tests and missions, so you should be prepared for that if you really want to play this game. I would recommend doing them all now while you know they can be done (as I just did it) before they change something and break it for months.
As others have mentioned, one thing that really pays off in this game is patience and persistence. You will be SHOCKED how much better you can get over time. I considered myself to be the bottom of the barrel driver and thought I would never be able to do anything in this game, now I'm raving in A tier lobbies online
If I can do it, anyone can, I am SHOCKINGLY bad at this game haha.
Keep at it and don't give up.