As others have said, it is probably an attempt to convert you. Obviously, Mormons believe Mormonism to be correct in the same way the Catholics believe Catholicism to be and, in the same way we do, think that ideally everyone would convert to their faith. This is not a bad thing, so long as you’re prepared for it, since it also opens up the possibility for you to present your faith to them. This could easily lead to discussions about faith between your two families, and in discussions (that go anywhere) it is necessary that both sides have their say - or, to put it another way, no one will listen to you if you don’t listen to them.
Me and a good protestant friend of mine have each been trying to convert each other for the past 10 years, and while neither of us have succeeded, we have each learned a lot about the other person’s faith and about our own - I learned that faith alone is a bit more nuanced than I had originally thought (though he has yet to convince me that it’s right), and I managed to convince him that we do not worship saints and that praying to them is not entirely insane (though so far as I know, I haven’t convinced him to actually do it), etc.
So it can be valuable for both of you. Again, so long as you’re as prepared to defend your faith as you have to assume they will be to defend yours. Just be aware that in any sort of conversation of this type, there will be arguments that sound convincing which you will not be able to immediately respond to and will have think about and research and, if you are willing and able to put in the effort it can be good.
As we say about math, the best way to learn something is to explain it to someone else. It can be a good thing. But if it goes beyond a simple visit to each others churches and turns into a series of discussions, you’ll need to be prepared.