House hunting tips for a millennial who's never owned one

I'm starting the process of looking to buy a house. My partner uses a power wheelchair and anything we buy is going to need to be accessible or modifiable. So I know we're looking for a ranch, probably 3/2 at most is what will be affordable but I'm finalizing my pre-approval now.

That said... I'm almost 40 and I've never bought a house before. What are some things I need to know when looking at a house? I have a realtor and we're looking at our first place tomorrow. I'm bringing a measuring tape because the accessibility will matter.
But I don't even know where to start and what the normal questions are!