<human>: Lola[30f] and I [28m] have been together 3 years. She has a young daughter who I have become a second father to and we've all lived together for about two and a half years. 

Nearly ever since we have been together I have been incapable of making decisions. We had a rough beginning as I was a complete pothead and trying to figure my life out while getting out of some debt. She had a steady job and was supporting her child. But we balanced each other out at that time.

Now I have a steady job, I take care of a lot of housework, nothing special, though. But my inability to follow through and make decisions is putting a serious road block in our way. I consistently offer to take care of things to help out since she has a lot going on but I keep botching things. 

Ridiculous things like not confining an appointment at the vet without consulting her, running to the store and calling home to make sure I didn't forget things. We recently got engaged and i wasn't really taking part in the planning of the wedding that we wanted to make happen quickly. She is getting tired of my inability to carry on a conversation when the shit hits the fan and I'm just left with my mouth shape and not a single word in my head but "I'm sorry" and "I'll try harder"

Its no wonder she is frustrated and can't see me growing up and taking responsibility and I'm at a serious loss for how to fix this, to fix myself and show her that, after all this time I keep screwing up, that I can really step up. And I don't even know how to do that. How can I possibly salvage this?

Give me the gist of the text in a nutshell
<bot>: lack of confidence and follow through are tearing my 3yr relationship apart and she can't tust me to take responsibility, how do I show her and convince her I can step up after all this time?