how long do you wait to help with shedding?

I bought a baby ball python Sunday evening. There were no apparent signs of a shed, but he started around noon today. It started out fine, but then progress stopped at the back of the head on the upper half and continued on the lower. He's made more progress, but still uneven. It's been about 8.5 hours now, he's gotten about 5 inches on the back and about a foot on the belly. Should I just let it go since it looks like it will all come off and just check to be sure afterwards or do something to help things along?

I'd say bump up the humidity a lot and let him do his own thing, even if it's in pieces.

Oh, humidity, I did at least do that once I noticed the shed. Thanks. That was really what I was thinking, but it's my first snake (so obviously my first shed as well) and all I can find by research is how to help but nothing about when. I'll let things go and then check for left pieces after. I at least know the eyes are good. I am extra impressed now by temperament. This snake was very ok with being handled both by myself and my nine year old daughter, never even balled up, (though it did pee on me) and all the while (s)he had a shed coming!

Right, but there's really no need to intervene. If it doesn't all come off, as long as your husbandry is correct it will all come off with the next shed. It's really only dangerous if you constantly have low humidity and bad sheds build up over time.

Check that the eyes are clear, the tail tip is clear (old shed can cut off the blood supply and cause problems), and there's no ring of shed around his middle that could interfere with eating. If those are all good, just keep his humidity up and let him work it off.

Ok. I've just been doing research because if I'm going to have a pet I want it to be happy and healthy and a first snake is a big difference from my dog and cats. I'd find both that bad sheds can cause problems (or be the result of them, but I'm not taking too much blame for this one being a day and a half after purchase) and that my new baby likely already got a bad start coming from petco.

I know the eyes are good because it had just gotten past them when I first noticed the shedding. First chance when he finishes, I'll get him and the skin out and see how everything is looking. Thanks for letting me know what to look for.

Out of curiosity, any noninvasive ways to determine gender? I hate using “it", and my daughter really wants to know, but not nearly as much as she is vehemently opposed to normal methods because she's afraid they'll cause discomfort

There is no way to tell the sex noninvasively. If you don't want to personally pop or probe, you can find a reputable breeder in your area and they can do it for you. I watched about 500 youtube videos along with being shown by a friend who's a breeder how to pop correctly. It's definitely weird at first, but also shouldn't cause any discomfort. I mean, having your genitals messed with is probably uncomfortable for anyone, but I'm not sure if a snake has the ability to even tell if it's feeling violated :D

*I* believe that I could take it to someone and have it sexed pain free. I even suggested asking the people at the reptile museum in town to which I'm taking my preschool class for a field trip in a couple of months. It's just a bit more difficult to convince a nine year old of this. This child also gets upset if I have to force feed a pill to one of our other animals even if they'll help it, or even in the case of my dog refusing his heart pill that will prolong his life. I may try and see if one of those people can explain it to her better. Cuz moms are not always the most believable sources, of course.

Someone say violated?:P I found out my wild caught (adult) corn snake was a male when he got too close to our female butter corn and dropped a little sperm.

Mine always had issues with shedding. It would come off in pieces and take forever. I got one of those repti foggers and a hygromometer to maintain the humidity level. Now he sheds one full piece, couldn't be happier. If me having to spend a few $ is all it takes, so be it.