raley, boxing is great.
check out the different gyms in your area. if you can, go to an off-campus gym that has at least a few pro-fighters. you'll get a better workout than a "cardio-box" type gym. about getting hit in the head repeatedly, don't even worry, you're gonna be fine. first of all, you won't spar until you're good enough to. second of all, you won't spar enough or hard enough to sustain long-term damage. third, pro-fights (no headgear, lighter gloves, many rounds, cutting weight) are what mess people up and you're a long ways off from pro-fights. fourth, like the guy with the gun said, you'll be wearing headgear and using 16 oz gloves.
like Tck13 said, Muay Thai is also a great alternative. again, try to find a gym that has a few pro-fighters, not a tae-bo thing.
since you said you wrestled for 6 years, let me suggest you try out brazilian jiu-jitsu. i don't know the area too well, but here are some teachers that might be worth taking a look at:http://www.leonardoxavier.comhttp://www.travistooke.com
both have a lot of competition experience in brazil. travis tooke is a wrestler as well, so he might be able to transition better. if you start doing bjj now, i guarantee you, you won't regret it (and wish that you started earlier).
also, if you like to compete, BJJ has a lot more opportunities to compete at an amateur level than boxing.
if you STILL want to box, then, let me suggest one more option: MMA training. you will learn how to box, clinch, and work on the ground (submission wrestling) AND also use your wrestling. there is a very famous fighter in houston who has a gym:http://www.revolutiondojo.com
yves edwards is pound-for-pound one of the best fighters in the world and he is based out of houston.
another school for mma is:http://www.defend.net
they have a very wide curriculum which you might enjoy. they even have a reputable former pro-boxer teaching there.
there you go, hope you find what you're looking for.