It's rated "A," which Marvel indicates is material, "Appropriate for ages 9 and up."
I think their ratings system is sort of silly in general, but I was sort of surprised to see that "A" on the back of the back cover, instead of a "T+" ("Appropriate for most readers 13 and up, parents are advised that they may want to read before or with younger children") or "Parental Advisory" ("15+ years old similar to T+ but featuring more mature themes and/or more graphic imagery. Recommended for teen and adult readers").
I can't imagine Loeb and Cho were thinking about nine-year-old readers when doing that locker room scene at the top of this post, for example. (And man, what the fuck is up with Spider-Woman's gesture in that last panel? Is she stifling a laugh, or eating an invisible banana, or...?)