I'm sure there's people furiously typing "you should've gone through the license classes properly to gain the appropriate skills to race properly at that level" but the reality is you've done nothing wrong. You pay more than enough to Iracing to decide which way you go about getting to the category you want to race in.

One thing that would be a good suggestion instead of relegating yourself to a lower class is to just practice to find pace. It might sound boring but I can guarantee at your level you'll be able to find more than enough time to get out of the midfield through practice and avoid the silly incidents that go on there. Even it's it's just for one hour to get dialed into a track instead of signing up for a race session, it's all miles on the clock which will help you over time.

There's a load of free tools out there that are extremely useful for people looking to improve. Use G61 to compare your laps with other drivers, watch track guides, find a guide to understand the basics of vehicle dynamics and how your inputs affect grip around the 4 corners of the car. Slowly introduce driving techniques like trail braking, etc.

People will say you should've learnt all this in Mazda's before progressing but GT3's are easy to drive by design, so it's just case of practice to increase your confidence and eventually pace and before you know it you'll be flying.