Whether or not you'll get stretchmarks is about 70% determined by your genetics and 30% influenced by keeping your skin moisturized, eating right, and staying hydrated.
I didn't get stretchmarks until I was in the hospital to get induced (the IVs made me super swollen and I was bummed), but in case you do end up getting stretchmarks, I did body scrubs with coffee grinds, sugar, and olive oil. (Coconut oil breaks my skin out). It helped fade my stretchmarks, and it's a great exfoliant for your body in general if you want glowing skin and I don't have any loose skin whatsoever.
(Pictures are from October 2013 and May 2015 to show time lapse. My daughter was born December 2013)
Congratulations on your pregnancy and I hope this helps.