It's strange becoming an elder, because so far it's less in my own mind than in other people's perceptions of me. I still occasionally startle when I realize I'm a grandmother, and that's largely framing because I don't startle when I think about my grandson. Being a grandmother, because of the way we use language and the way we think of self versus other, is an intrinsic change, not just a new relationship. It is a new identity.
I spent a lot of time and energy figuring out how to be a parent: I read books and magazines, went to classes, talked with friends, and analyzed my childhood for things to avoid (and the occasional thing to incorporate). Grandparenting is a far smaller time burden and less important given that my son and daughter-in-law are good parents, but it's still something I want to do well. Or rather, to reframe again, I want my grandson (and any other grandkids) to have a good grandmother, to have good memories of a grandmother who cared about him. Someone who shared exciting experiences and knowledge with him and thought he was terrific. Someone who showed enthusiasm for him, for his visits and his goals, for his trials and accomplishments.
I haven't given much thought to being the elder parent of adults; that seems trickier, but it also happens over a longer period--I'm not debilitated or chronically ill, and in need of care and someone to make decisions for me, just yet.
We plan and strive to become adults, and while we're adults, we plan and strive for more of the same. But there's no good guide to help us learn to change into elders. To accept the growing limitations on our abilities that are the mirror of growing into them in the first place as youths, to renegotiate the relationships that change from dependent to independent to responsible. Suzette Hayden Elgin, renowned linguist and science fiction author, often discusses eldering on her blog; it's worth reading.