Recommendations for FPV Sims Before My First Build?

Lift off

I'm in a similar boat, and have also been looking at this. What I found out from research online is:

Velocidrone for a low performance PC

I used Liftoff for 2 months straight last winter and was able to fly with no problems my first quad in Spring. I started with the Pocket and recently switched to the Jumper T15. I have built a 5 inch and a 7 inch quad in the last few months lol. Haven't even been in the hobby a year yet. 

Lift Off and Lift Off Micro drones are both pretty great. People also have uploaded a lot of builds to the workshop so you can try and get something similar to what you would fly. There are plenty of BNF type builds already on there.

Get uncrashed. multiplayer, map editor, racing. its the best. also get a set of 20mm M3 threaded rods off amazon and a set of M3 ripsticks for your pocket. longer sticks are way better. i like the standard shape.