NTA. And, as someone whose MIL moved across the country to 'provide childcare' for our son, don't do it. My MIL is a lovely person and a positive influence on our son. But, the dynamic it has created, having a third wheel in the parenting mix (who just happens to have raised the only other person of the three who isn't me) creates a de-facto 2 on 1 situation in almost any dispute, argument, big decision, etc... That, and her husband (not my SO's father) is insufferable. So, even if she's single now, you run the risk of her shacking up with God knows who in those nearly two decades. And, I'm here to tell you, no matter how angelic the MIL, the combination of her and a constantly braying jackass as permanent fixtures in your everyday life is, to put it mildly, not fun.