On my experience it is very different. I fall in love with a person not an age. Sure everyone changes with puberty and teenage years but it is usually on their end when relation ship ends. Usually we just lose contact.
But I think I would love my LGF until the end and her growing up will not change that. I can not explain. It is her. I love her. If by miracle we end up together I will love her when she is 70 and I am 100.