Yep this is 7.22- "A Ripe Young Age" SSN 7 90210. This is an awesome ep and makes you realise (if you hadnt already) that David and Donna were destined for eachother!! :D
This is Beverly Hills 90210. Not sure of the exact name or season but its when Donna and David go visit Donnas grandma and she says her grandma wont talk about her deceased grandpa or enything and before she knows it she starts ipinapakita them pictures tells them the whole story and gives them pag-ibig letters to read...and tells her the tumawid that she got for her baptism was the one her grandpa used to wear when he was in the war and ect. yes it is 90210. :)