I don't think your size should be the deciding factor. I was roughly your size as a freshman and around 170 as a sophomore; I played LB all the way through college. I was also hilariously slow, but I loved to hit people. If you don't love to hit people, and you're not fast enough to be a "small skill" guy, then you're probably playing the wrong sport. Wrestling is an awesome sport, too.
Taking a year off is a terrible idea. First of all, you'll be an outsider to the team when you come back. While all of the other sophomores were taking their lumps from the upper classmen, you were fucking off in the gym. Second of all, since you're not a phenomenal athlete, you have to know the game better than the other guys to be worth a shit to your team. You're not going to learn anything sitting in the stands. Finally, the coaches are going to look at you as a "me-first" guy. That means that if you're close in skill to another player, but that guy paid his dues on the scout team sophomore year while you were dicking around in the gym, then that guy is going to make the starting lineup, and you'll be on the bench.
My advice, if you decide that you do want to play football, is to stick it out through your sophomore year, try to make a name for yourself as the guy that isn't scared to take his licks from the older guys, then work your ass off to gain some quality weight in the offseason.