What do you think?

If you love the name Alaina you should stick with it, you've had it for 5 years, no way, don't change it just because she'll have a cousin with a similar sounding name, infact I think it's cute and lovely that they're similar names, wouldn't it be sweet if they grew up together and became really close? Don't change it, you had that name first and to choose another name that you know deep down isn't as good as Alaina would only make you regret it. Good luck! x