7 degress is a lot. You can think of that has having a ton of up elevator trimmed in to the plane, so when you lift off, you're already holding way too much elevator, so you stall quickly and crash. (It's not a totally accurate description, but it's close enough). Adding more up elevator makes it worse. You might be able to acheive a sort-of counter to that with lots of down elevator trim in the air, but it's not the way to go.

Raise your TE a little and get the wing down to 0-2 degrees positive compred to the stab and try flying it again.

While your wing does have a flat surface airfoil, You do have the flat on the top of the airfoil, which makes a huge difference. That's good. And your LE is sharper than you might find on some planes, but isn't all that sharp as these things go. You should be able to fly that wing just fine. LouW is correct, though, that those elements of your wing can cause a more pronounced stall, depending on the wingloading and other factors.

Oh, one other thing, since your ailerons are coming off the under side of the wing, check to make sure they are slightly reflexed upwards, and don't droop at all. That just adds to the incidence and creates other problems as well.