my clearance is 23 inches.... some such nonsense about having to be higher over a gas range. don't remember exactly what code was.
perhaps check into that...

The instruction booklet should have the min distance stated. Mine seems low, but is min distance. Never thought of the actual size of MW. It is bigger than the norm due to the extra grate that can be used. Am short too and have had a few mishaps pulling hot food out of it.

Am beginning to dislike the OTR, seems like every time I need it, when another is using the stove, the person has to be moved. Plus dropping something on the stove top is a concern. Considering minor move of stove to the left of the MW. There would be more working space too by doing this, plus avoiding boiling pots or frying to reach over.

My OTR microwave instructions were 30" min clearance between the bottom of the cabinet and the top of the cooktop. I have 32" total, so my microwave is about 16" over the gas cooktop. It passed the code inspections at that height.

I have just shy of 18" from the grate top to the bottom of the MW. We find that to be a good height.

My last set-up had less clearance, maybe 16" - microwaves hadn't been invented when the kitchen was built, so this was a retrofit. That height was great for putting stuff in and out of the MW, but crowded a large pot on a back burner. My mom had one that was higher, maybe 20" and it was ridiculous. I was always afraid she was going to dump her oatmeal on her head. Mom was about 5'1 or 2" at the time. I was not sorry when she fried that MW with a foil container and we replaced it with an on-counter model.

I think the height you have will be fine, but I have a question. Is there any way you can put your MW somewhere else? Ours is there because our kitchen just doesn't have any other possibilities that make sense, but I'd much rather have a real vent hood and MW elesewhere.

P.S. meganmca - the venting doesn't have to be fake. My mom's was because the guy who flipped her place moved the stove and MW over a bit and didn't bother to fix the ducting (we found out when we removed the fried MW). Because ours was originally a vent hood, we just hooked the first generation MW up to the existing vent pipe. That MW lasted for nearly 20 yrs. BTW. When we remodeled, we moved the stove over a bit, but we still made the vent connection work:

Not to say that a MW vent system is anything like an actual vent hood, but it's much better that nothing.

Mine is 17 1/2 ". My last one was less and easier to use since I am short as well, but I am getting used to this one....pulling a big, hot Pyrex dish out can be difficult, but I'm usually just microwaving simple, one dish things.

18.5 inches.