AITA for moving to be closer to my grandkids

I have 3 kids with my ex husband; Elliott (28), Emily (21), and Joseph (19). Emily and Joseph still live at home while they attend the local state university.

3 years Elliott married his high school girlfriend, Madeline (27) and they have 3 beautiful little girls. Sophie (12) is Madeline’s half sister that Madeline and Elliott adopted 3 years ago. They also have 18 month old twin girls, Charlotte and Penelope and they’re pregnant with their first son.

Last year Madeline and Elliott moved from their apartment down the street from me to a house about 3 hours away for Elliott’s job. I try to visit them at least 2 weekends a month and I just love where they live. It’s this adorable little quiet beach town. I’ve been thinking about retiring there since Elliott and Madeline moved down there but I made the decision after I found out Madeline and Elliott are having another baby.

I put in an offer on a little cottage on the beach, a 10 minute walk to Elliott and Madeline’s house. My offer was accepted so I decided to sit Emily and Joseph down to tell them my plan.

I told them that I would be selling the house this summer and moving closer to Elliott and Madeline for an early retirement. I didn’t want them to struggle to find a place to live so I told them I will rent an apartment for them to share for 3 years or until Joseph graduates, whichever comes first. Neither will pay rent or any other expenses besides part of their groceries as long as they’re still in school.

I thought Joseph and Emily would be ok with this but they were furious. Joseph is saying that I’m choosing Elliott and my grandkids over them and Emily is claiming that I’m misusing their child support (their dad agreed to pay until they graduate from college) because I won’t get a “good” apartment (I’m getting them a simple 2 bed 1 bath apartment in good condition close to their school instead of a luxury 2 bed 2 bath with access to pools, a gym, and other nice amenities). I told her she’s welcome to pay her tuition and living expenses on the $850/month I get from her dad and now she and Joseph won’t speak to me.

Elliott is suggesting that I could’ve given them more notice and talked to them about this before I bought the house but I thought 3 months was plenty of time.

AITA for moving to be closer to Elliott, Madeline, and my grandchildren?