Is it normal for my parakeets to be acting this way?

Hey guys! My dad recently bought me two parakeets a blue one and a green one. Supposedly a girl and a boy. I am pretty sure they are still not fully developed yet because the green one still looks a little chubby and his tail is barely sticking out. And the blue one is bigger than the green one but her tail is not very long. Anyways I just got them on Sunday and i don't know if its because they still aren't used to me or because they might be sick or what. I change their water every morning. In the morning they will be kinda happy and cheerful but by like the afternoon they will just stand in their cage. And they will stay like that for a while until i go and see them and they move bc they're still scared of me or if they move bc they're hungry. They also don't really chirp a lot only every once and a while and its kinda rare or when the tv's too loud. The green just took a nap in the middle of the afternoon. I'm not sure if thats normal. I'm not sure if its normal that they are just standing around for long periods of time in their cage. Do you think i need to buy more toys for them bc they only have a swing. Please help guys. If you guys can also help me in what food i should get them, bath, and toys and anything else you guys buy for your parakeet. Please help guys!! thank you so much! I really want to know if they are sick or if its normal bc they're not used to me or what.