Do not be afraid,, easier said then done I know, But you love to build so rebuilding isn't an issue anyway.
As stated above you just need a good plane that will help you master it all.

Sig kadet sr is an awesome trainer as well as the Carl Goldberg Eagle 63 you will find success in both.
Moving to a low wing plane I'd recommend the Sig 4 star 40 or 60 or the Carl Goldberg Tiger 40 or 60 both great low wing planes that have a great stabile platform to ease into low wings.

The messerschmitt 109 can be a bear to handle until your used to low wing planes.

But just getting up there with a good trainer plane and practicing those touch and goes will greatly improve your skills and help with that knee knocking adventure. I've been flying for over 40 years and still can produce a good knee knocking every once in a while but after the first landing weather it it be a 2 minute flight or 2o the knees don't knock. I kind of miss that lol.

I too love to build them and fly them, I never worry about flying them because if I crash a couple of hours with some glue and shes right back together again. I don't think anyone wants to crash, and with great care you can really minimize the crash factor, good preflights and checking everything before the flight is all you can really do. but like anything something, anything can happen. be careful, be patient and practice is all it takes.

if you can get on a buddy box that would be the easiest way to learn it right, many of us didn't have those options growing up and it cost me many plane crashes, But I was a kid and loved to re glue every night anyway. each week was a little better and a little less damage until the Eagle 63 showed me the light for my very first solo take off and landing. it was well worth the ride. I train many people now and really have a lot of praise for the buddy box system. it helps a great deal for a flyer old or new gain great amounts of confidence in a very short time.