In-Laws are Crazy!!
With families and in-laws, relationships are important. When I was dating my husband, I'll be honest, I thought his family was SO WEIRD! especially when it came to meeting them for the first time. One of the things that my husband told me was that his family is important. This is probably the quality that made me love him even more because that's how I feel about family. Family is important to both of us and we try to spend an equal amount of time with both our families.
Learning from his family and eventually getting to know them better. I have gain better relationships with each of them even the nieces and nephews.
I'm sure people have had a worse first experience meeting their in-laws but I know as you try to make it work with them, you'll have good friendships with them. Make sure not to judge and try to look at the things they tell you from their point of view since you haven't known them your whole life like your own family.