My daughter got a guinea pig for her 12th birthday as well!

She had begged us for her 11th and we told her that if she still wanted one a year from then she could get one. (Her friend had just got one so I thought maybe it was just a hyped up wish).
She talked about it for that whole year so we knew she was serious.
She did go and hold several and picked out her favorite - his name is Charlie. We all LOVE him! They are so funny to watch.
We don't do bedding - we do the felt blanket over a towel method and it saves on bedding. Basically you put a towel down on the bottom of the cage and then put a blanket of felt over it...it wicks down into the towel and you just wash both. I do one load a week of just Charlie's bedding.
Just make sure it's a solid surface bottom on the cage otherwise it's horrible on their paws.
We do give pellets but the majority of his diet is fresh veggies and hay - mostly dark greens (kale, spinach, etc.) They can NOT have onions - they are deadly to guinea's. I believe cabbage is a no no due to gas issues. Also only dark greens...no iceberg lettuce, it can give them diarrhea. He wheeks when we open the fridge - he knows it's dinner time. He eats just about any veggies we have - colored peppers, cucumbers, tomatoes, green beans, carrots (his FAVE),grapes are another favorite. He also likes pieces of fruit on occasion (apples, bananas, etc.)
We let him out on the kitchen tile to run around and he loves it! She has to watch him though because he likes to snack on my wood trim and chair legs.
Charlie is like a real life doll to my daughter - she dresses him up, bathes him, cleans his cage every other day like clockwork and is 100% responsible for his care. We do "pig sit" but he's a piece of cake compared to any other pet.
I think guinea's are a great pet for a 12 year old...they are work, but all manageable tasks at that age.
