Is it selfish to try and get a dog?

I have my cat Nairobi who will be 4 in august. She’s not the biggest fan of other animals however I do feel like she’s never been properly introduced to one. She is a scaredy cat and can be skittish at times. I would love to have a dog in the house and I was thinking a relatively small dog (10 pounds at most). Is it selfish for me to try and adopt a dog and introduce her properly? Is this just a bad idea all the way around? I feel like it might be bumpy at first but with time I feel like things could even out? Thoughts and opinions?