First ever motorcycle

I’m 33, I’ve never had a motorcycle before. I guess I’ve always been a little curious but it’s only recently I decided I want to actually invest in one.

I’ve decided I want to get either a Ninja 400 or 650. I went on Facebook marketplace and found a used ninja z400 abs. Is that basically the same thing as a 400 or is it something completely different?

For reference, if it matters, I’m kinda a big-ish guy, at 6’2 and 210 lbs.