I agree with Rodney.

More than one thing may be wrong, and you need to learn each.

I see no reason for that person, who is "considered as the best at that field", not to take more time than "a quick look" with your trainer and teach you how to trim it properly.

It is much easier to trim a plane "hands-on" than from a distant forum like this.

Just ask for help at your club, somebody will help you properly for sure.