Old people as a group don't exist. There is no monolith based on simple traits like age, or race, or gender. While more members of one specific group sharing any of these traits can be likely to trust or mistrust or agree with anything, boiling them down to a singular opinion or mental state is always wrong. It's discriminatory.
You saying old people as a group do trust AI is as fucked up as saying that black people as a group do love watermelon.