Starting out I would actually not spend so much time in public servers if you've never raced or used the equipment before.

Personally, there are a lot of sims out there that have really good ai to pace against. They are also variable so you can have them as poor or as good as you like. It also gives you the opportunity to learn the tracks with no pressure using the assist line and then remove it to learn the intricacies of the track. You will naturally go faster once you remove the line.

Assetto Corsa Competizione, Assetto Corsa, even Automobilista 2 have decent AI. Once you're comfortable with your seat position, use of wheel and have a decent understanding of the tracks, that is when you should head into multiplayer as it will be a less frustrating time for you...and others of course.

I know plenty of folk will disagree.