Chewbacca being a Wookiee (who live for centuries) means he ages at a different rate to Han. One of those interesting character questions unique to SF&F.
In the OT we were catching Han and Chewie at the moment when they were both the same age (So to speak). Equals, brothers in arms. In TFA Han is much older than Chewie and we see Chewie making sure Han wraps up warm against the cold, like a caring son. So in a young Han Solo movie will Han relate to Chewie as something of a big-brother, or even a father figure?
That’s quite an interesting angle to their relationship that has never occurred to me before.
I seem to recall Lucas having planned to include a young Han on Kashyyyk in ROTS where Chewie undoubtedly would have been a sort of father figure to a 12-ish year old Han. So even Lucas seem to have thought about this side to their age/aging difference.
So I hope the directors of the new Han Solo film realises this and make Chewie seem older in his personality. It would be interesting to see a young Han Solo following Chewie around, as opposed to Chewie just being the “side-kick”.