As someone who lost thier mother to cancer, I can fully sympathise with you, and even thinking about it now wells tears up in my eyes.
It's been 9 years now since my mum passed, 5 years ago for my dad, and yet I still find myself reaching for the phone to call.
As someone said above, you're going to go through a FLOOD of emotions, some you're not going to feel comfortable with. It's not going to seem right to be laughing about something at a time like this, but in remembering your life with your mum, you're going to remember some funny **** that you'd forgotten about. Trust me, it's alright to laugh about it and to spread the humor. It's also perfectly alright to just suddenly burst into tears for absolutely no reason at all. It took me two years to stop doing that after my dad was gone...... well maybe not. I still (occasionally) have it happen.
My thoughts and prayers go out to you and your family. And yes, you're right. 47 is too young. Hell, the 58 years my mum had weren't enough.