I basically have TWO sets of in-laws since DH's parents got divorced when he was 3, each remarried and went on to have 2 more each. So there's 2 sets of in-laws and their kids... AND I ADORE THEM ALL!!!
They have been so welcoming from the very start, which is awesome in and of itself, but when you add to it that I'm 10 yrs older than DH, his mom had him when she was a teenager, so I'm only 8 yrs younger than his mom... it's kind of especially wonderful that she's been so supportive and approving of me as his wife/mom to her first grandchild.
Both sets of in-laws have been very supportive, they all call me to see how me and the baby are doing (even though they call their son directly too to check, they check with me also because they know I know more!
) And a couple times when DH and I have been going through a really rough spot, even though I'd never initiate a conversation about it, they have checked in on me and I've shared a little of what's going on and they always talk to him in a really supportive way (supportive of both of us) and they have helped us get through 2 of the worst fights we've ever ever had.
We just got back from a trip to see one set, and the other set is coming to visit later this year. I feel really lucky, they are all great people. And my parents ain't too shabby themselves - DH really likes his in-laws too!