question about tamagotchi P2, 1997?

i think that is what i have the p2 version.

now it is 25 years old, it seems that its happy and hungry meters going down really fast, like 4 stars in one hour. i have to constantly feed and play with it now.

i suppose that it is normal?

how long can it live? forever?

That's normal for vintage Tamagotchis. The older it gets, the more demanding it becomes. It'll probably live for as long as you can take care of it but at some point, it will go back to Tamagotchi Planet because if you're like a lot of people with busy lives, it just gets to be too much. I'd say the neediness is really noticeable starting sometime after the 2-week mark.

how do the new ones do when they get old?

The new tamagotchi, I find, are less demanding as they get older. Mostly because as soon as the MatchMaker, or the Date Place becomes available, we take them to it to get hitched and raise another Tama Baby.

But in my experience, I've noticed that as they get older, the less care and attention they need. It's almost like they can take care of themselves, or are perfectly content being an adult.

If the above graphic is shown properly, you should see a blue U-shape curve and a green L-shape curve. The high left end represents the high level of care you need to provide when a Tamagotchi is hatched. As they grow from baby to toddler to teen to adult, their care requirements go down, as represented by the low position of the curves in the middle part of the graph. On modern Tamagotchi models (those released from 2004), care requirements remain steady as the character advances into old age. In contrast, vintage models (those released before 2004), care requirements increase after a while. At around age 14 (depending on the adult character you have) it starts to accelerate. By age 21 the day-to-day difference is noticable. By age 25 (again, depending on the adult character you have) it's almost impossible to satisfy their care requirements.