We have a great dane and a mi-ki...170 pounds and almost 5 pounds, but they still keep each other company! There are a lot of pros and cons, it may not be an easy decision. Remember that you will have twice the poop and pee to deal with. But you will also have twice the love and Layla will have company. But there is the off chance that she won't want to share her mommy. You may just have to get Layla a dog and see how it works out
I know getting a dog is a big commitment, but it's sometimes hard to have all of the answers beforehand. Good luck kiddo!