My mom checked with Petco?

She said that the petco woman said i can get one rat. I just have to spend all the time in the world on it. Which isn't a problem. I would love to walk my new rat. Train he/she. Love He/She. Play with he/she. My cats wouldn't be a problem. Tiger would probably just hiss for a week then theyll be just frinds. Tiger just plays with rodents. he doesnt hurt them. Is it okay. I have lots of free time.