i gotta tell you, i had three pet rats and they were WONDERFUL. just think of how close this little one will be with you if you raise her! (i do believe it's a girl, btw).
the thing is, i'm not sure baby rats drink esbilac. you'll need to do some research to make sure your baby gets the proper nutrition, and you need a reliable source. i suggest you find a forum like this one that offers many experienced opinions on rat care- a checks and balances system is best!