Am I the only one who has problems enjoying this picture? I mean the doe-eyed innocent look is great and everything when a girl is giving a blowjob, but in this one, it makes me feel somewhat...dirty.

Great picture regardless.

It doesn't help that she seems to have the "Going unconscious" face

If by "somewhat...dirty" you mean "hard as a diamond" then I feel the same way.

...Isn't Sherry like 8?

Welcome to the world of hentai. I guess you won't have seen the 13,500 other loli pictures on Danbooru because of your user level - this one should be tagged as loli as well.