I'd say just keep riding your KLX as it is. As your riding ability improves you will get more comfortable on the bike.
This is what happened with me. My KLX seemed too tall at the start and I even bought lowering links as a result. In the end I never installed the lowering links and now I am completely comfortable on my bike at stock height. (Anyone need lowering links?)
BTW I am 5'8" with 30" inseam.

 

There is nothing intimidating with the 250 and your height. I am about 5'5" and have a 28 inch inner seam and although not flat footed, have a fair amount of contact with the ground. Just make sure you have your sag set correctly. You should have about 100mm.

 

I dream about having a 28 inch inside leg. 26 and wobbling😢

 

I would suggest buying lowering links from canKLX and raising forks in triple clamps (lowering front end as well as rear). Hold tight to original rear shock dog bones (links). Ride until your confidence improves and you feel comfortable on bike then revert back to stock so you will have "proper" handling...