Got Back With my Ex

Hey, so my ex and I got back together recently. But I don’t know how i feel about it. I want to be back with her but I feel like we may be rushing things. The reason I say this is because when I talk to her it’s just like our old relationship. I feel like we haven’t established a new one.
Obviously our old one didn’t work. I’m just not sure how to implement new things to it. I know i should read Relationship Rewind more but I need some immediate advice.
Should I tell her I think we’re going to fast? Should I also bring up the idea for us to write down everything we didn’t like about the relationship before so we can focus on forging a new one? Lastly, is the sooner the better?