We Have A Female Boxer About 7 Years Old. We Are Wanting To Get Her A Friend, Would It Be A Problem If We Got Another Female?

I have grown up with Boxers and love them for their loving and gentle temperament. We are wanting to get another boxer puppy as a friend for our Nikita(7 yr old female Boxer). We were wanting to get another female that we could perhaps breed with eventually. Is it unwise to have 2 females? Nikita is a very gentle dog and is excellent with our children(5yrs & 3 yrs), we have never witnessed her being anything but playful and happy with other dogs.