Is my 4.5 pound yorkie o.k. to breed witha 2.5 pound male ?

My yorkie rosie is 4.5 pounds i want to have a cute lil baby rosie running around too but i want to make sure everything is safe and ok before i even think about it i have a 2.5 pound male that is wiolling to b reed with her . is this ok ?? my mom said she is fine but i am 13 and i dont want to loose my best friend.......