Bibles an shit

So I received this bible from two missionaries patrolling my block. Now, backstory time. About a year ago, I started watching this show Jane the Virgin. This show encouraged me to discover god and start having faith. I am 13 years old, and I was raised by an atheist mother, and had an atheist father. My mother grew up a catholic and always told me how crazy it was. I know she loves me, and she supports me through nearly all decisions I've made, but I don't know if she would be okay with this. I asked her casually, and she rolled her eyes and said "I wouldn't drive you to church" I have been wanting to become a practicing Christian for a few months now, and even though the church is just up my street, I took that as a clear show of annoyance for my decision, and am now scared to tell her. I have been praying to god for guidance, or a sign, and I think this bible is a sign. I am firm in my belief and not likely to change. I know I have to tell her, but how?