Doubts about becoming a godmother

Hi, my cousin asked me to be the godmother of my to-be goddaughter, who's the daughter of my cousin. I'm a young woman myself. I was raised in a very religious family, though I had ups and downs. Actually, I was an atheist for a while, only to be slowly but surely turning more religious over time again. I agreed to be the godmother of my cousin's baby with great pleasure.

I was checking some requirements for what it requires, and I have all the necessary documentation of the sacraments, but the thing I paid attention to was that one requirement was to "lead a life according to faith." I sent this to my friend, who told me this certainly does not apply to me. I told her she does not know what is going on in my head, but she said she knows me well and I certainly do not live my life according to faith.

Now, like I said, I'm young (19), I party, I use substances, though not to excess. I'm in a relationship and have premarital sex (we discuss getting married, but yes, I am aware it's still a sin). Yes, these are sins. I am not trying to justify myself, but I have an internal process going on in my head about these things. I contemplate confessing and changing my ways. I consider her to be a relatively close friend, but I don't have to communicate everything to her. I don't communicate a lot of serious matters to her, that's why I told her she does not know what is going on in my head.

I probably sin every day in some other, less obvious ways, and I regret it. But aren't we all sinners? I have also been dealing with many particularly distressing struggles recently, major family as well as health issues, so this also hurt me a lot, as I've been trying to change some of my behaviour, which is even more difficult given these struggles.

So I asked her, where do you put the line between leading a life according to faith and not? She compared me to another friend who goes to church every Sunday, said I never go to church, so I am not practicing, and said, "You cannot put a line, but often you can tell." She said she did not want to offend me, but that I am not even trying and I should just accept it.

Now, I don't usually go to church. I didn't for a long time, but I did go a couple of times recently, and I contemplate doing this regularly. The friend she compared me to also comes from a different culture and has very strict parents. She has never once in her life questioned her faith; I did a lot. But yeah, it hurt me given the struggles, I don't have the need to confess to her everything that is going on in my life/in my mind so I think she was wrong to make such assumptions that I am not trying. But maybe it's my pride speaking, and she was right.

So I was thinking, should I even become the godmother? I am aware the task is to pass on virtues to the child, etc., and I can do my best in this. But where does one put the line when you start leading a life according to faith? I'm a sinner, but I will forever be one, isn't that true? What does living a life according to faith actually mean? I try, though it's difficult, and as you can sense, I have doubts, but I still have faith.

Sorry if it's chaotic. I guess what she said made me sad because I was excited for that role. But maybe she was right, and I am not the best role model. I guess I will ask people smarter than we are for their opinion. :)