It's so great that you have that final memory of exchanging I love yous before she passed. A lot of people (obviously) don't get that kind of closure and spend a lot of time with regret about that kind of thing. You'll realize later how helpful it is to have that finality to your relationship w/her.

I actually don't remember the last words my mother and I said to eachother, but like I said in my post below I have months worth of incredible memories w/her because we knew she only had so much time left so my dad, my brother, my mom and I made the absolute most of whatever limited time we thought we had left. So thankfully I have a kind of closure even if I don't necessarily remember our last conversation specifically.