Is this the longer or shorter rotation? If it is the shorter rotation, it might not be too bad and will certainly give you a taste of the challenges of teaching in difficult circumstances. If it were my wife or daughter going there, I would recommend they go visit the school this week (before school lets out) and get a feel for the place. Drive around the neighborhood a bit, see who hangs out at the times when school opens and lets out. If she felt like it was unduly dangerous, I'd tell her to do what she can to get a different placement. If you go and can articulate to the staff at the U why you think it is dangerous, I would imagine it will be easier to get it changed.
As Pearlbob pointed out, many Memphis City Schools are bad. Changing may not put you in a better place and may even put you in a worse school. My biggest concern about this school would be that it isn't in the greatest neighborhood, but it certainly isn't the worst either. I have a buddy whose wife taught at Raleigh Egypt Middle for a couple of years (and that is certainly one of the worst schools in town and also in a sketchy neighborhood), and while she didn't really enjoy it and is glad to be gone, she didn't express great concerns for her safety. My wife student taught in Frayser 15 years ago and would also say it wasn't a great school or area, but it did help her become a better teacher and she didn't feel like she was in danger at the school.
Another thing to keep in mind is that there may not be many white students at the school, but there will almost certainly be other white teachers. Your age and youthful apperance may be a problem in getting respect, but I wouldn't be overly concerned about being white at the school. Just drab up, get some severe school marm glasses, and show and demand respect. The good news is a 23 year old seems 50 to most 7th and 8th graders.
Here are a couple of links I found about the school:
http://www.mcsk12.net/profiles/WestsideMS.pdf
http://edu.reportcard.state.tn.us/pl...8194627775::NO
There appears to be lots of suspensions, so the administration at the school seems to take discipline seriously (a good sign).