They do all grow at their own pace as lismar79 stated. He does look in the right size range for that age. Please read Toms threads below in my post for proper housing.
Hello and welcome. You can get a kitchen scale and weigh him once or twice a week to check his weight gain. If you tell me his weight in grams, I can tell you where he is on the spectrum.
Want some tips on how to raise them? Most of the info out in the world is outdated and incorrect.
Hi Viri. Welcome to the Forum. Your baby sulcata is precious. Don't worry much about it's size for now. If you follow the diet and housing guides posted at the beginning of this section it will grow to be quite large. As Tom suggested, a kitchen scale would work great for monitoring its weight.