I'm not a veterinarian, so I can't give you health tips for your pets, but when it comes to weight, a human scale should work as long as it can measure a small enough weight. You might have better luck with a kitchen scale, but make sure your parents help you, and you clean it well after using it. I'd suggest putting some plastic wrap over the top of the scale. You may also need to use a glass bowl as your guinea pig may not sit still long enough to weigh it properly. I hope this helps.