He'll actually be closer to 30, especially if you count a Tag year. I don't see that as a bad thing to be honest. I get to eat cost controlled years, and never have to give the player a big pay day since he's going to be over the hill at 30. That's actually good for the team, bad for the player. If he's a good player, team gets to eat.
I definitely sit on the side of seeing Floyd as a big question mark but I'm not as down on him as some seem to be. I feel like his effectiveness is going to be defined by how much he can mold his body in an NFL strength and conditioning program as I said earlier. His weight isn't much of a concern if his frame wasn't so lanky and on tape, he does lack power. Put that up against NFL tackles with his hand in the dirt which is one way the Giants would likely use him (as well as stood up as a WILL in our defense more than likely) and there's cause for concern there. He bulked up to 244 for the combine and was still stupid fast and showed off his athleticism which is what has teams enticed and is the reason for his rise up the draft boards, IMO. He doesn't shed blocks well and he doesn't have an explosive "get off" that want to see from a "tweener" type player who is likely going to be use in pass rush situations coming right in from the draft (and not a full 3 down backer).
The problem is how do you project him if he drops back to 230-235? How "finished" is his body at 24 is the greater concern with his age FOR ME. Moreso then how long he'll play contract wise. Maybe it shouldn't be. Maybe I'm way off on that front. I LIKE that he has coverage skill. I LIKE that he's played a variety if positions for Georgia so there's versatility there that the Giants covet and Spags can move him around. Super clean kid off the field and a good teammate from all sources as well.
Linebackers are tough in today's NFL. At least in so far as projecting who's going to really work out but it can be so dependent on scheme in some cases (which I think is very much the case with Floyd).