Stretch marks depend on several factors including heredity, skin type, and obviously, how big your belly ultimately becomes.
If you’re concerned about stretch marks, you can apply moisturizing lotion to your abdomen and breasts regularly and make sure to drink plenty of water. Dehydrated skin is more easily damaged by stretching.
That said, if you do develop stretch marks despite your best efforts, take heart. The marks usually fade over time, and ultimately are a small price to pay for a beautiful baby.
I hope that helps, please post any questions you might have!