What are the ups and downs about parakeets/ budgies?

I've been wanting a parakeet for a little bit now. I looked up everything I could about many different type of birds. I am almost twelve and I am very responsible. My dad is willing to get me a bird, but only a finch. The problem is, I want a bird that I can actually interact with! He thinks parakeets are very loud and messy. I, for a fact, know that all birds are messy. Parakeets are only moderately loud, and you could consider them quiet compared to other parrots and birds. Can somebody please provide the ups and downs to having a parakeet and some *key* information that will convince my dad to get me a parakeet?