What week did they start checking to see if you were dialated?

Not til the last month, about two weeks before my due date. It's a bundle of laughs (not). But seriously they don't do internals till very close to your date (well in Europe anyway, don't know about the US). Take care

IIRC I was checked once, at 36 or 38 weeks.

But many doctors (and most midwives) no longer check at all. Such checks are pointless, telling you nothing about when labor will start or how long it will last. (But checks DO tend to make women anxious -- if they are dilated early, they fret about premature labor, and if they are not dilated at 38 or 40 weeks, they fret that will need to be induced. There is also the risk of introducing bacteria, or accidently breaking your water. And some docs may use the check as a way of stripping your membranes without your consent.)

So, while nobody can tell you if or when your doctor or midwife will offer to check you, I would recommend refusing the check.

They checked me at 38 weeks

For me 40 weeks and 3 days. Only because I had a stretch and sweep at the same time.

I wasn't checked until I went into labour at 40 weeks and 5 days. Am in uk so don't know if it different elsewhere !

At week 37

No reason to check before you're active labor.