It's called "2 foot-itis". You're always wanting to go a bit bigger. I went with the 21 ft for a couple reasons. First, my kids are 5 & 7 so they're no help launching, although my wife can back the truck in and do whatever is needed. I felt the 21 ft was a bit easier to launch and recover at the ramps we go to. Not that it was a fully deciding factor, her statement of "It's too big" (which immediately warranted a gutter response on my end) ended the discussion of the 24 ft. For you first boat, the 21 is plenty big, we came from an 18 ft, and it comes with all the bells and whistles. No need to really upgrade anything, unless you wanted to. It has the ballast tanks, stereo, trim, you name it.
Now the 24 ft is a fantastic boat, don't get me wrong and chances are you're not going to need to upgrade anything inside that boat, the Limited SE is loaded as well. But, you don't have, someone correct me if I'm wrong, the ballast tanks. Not that it's a deal breaker, but it's nice to have them just fill and go. You do however, have the "throttle by wire" which is nice. If you were on a lake, I'd say go with the 24 and make the jump to the 242X. I mean, hell, you're right there, only about $6k away and well worth it to get the wake series. So, I'd say, if you can get the 24 LTDS, do that or make the jump to the 242X.
We started looking at the AR210, then jumped to the 212 Limited S, and I said "well shit, I'm here, and splitting hairs at $60k, I might as well get the 212X.
I hope this helps and not make your decision more difficult. It's a boat, you're gonna have fun no matter what you get. Remember that. And when your kids are older they're not gonna say "remember when dad threw that extra cash into his 401k? wasn't that great?" No, they'll remember the boat, 21 or 24 foot.