Buy kit for grandparents?

I’ve been wanting to buy myself a dna kit but is it a better idea to buy my grandma and grandpa their own dna kit first? They are close to 90 years old so this would be the time to do it and they wouldn’t ever bother buying their own since they don’t really care for it. My reasoning is that after I get their dna submitted then my results could be reflected better, or am I just overthinking it and just get my own?