I'm also own my own business with Arbonne and found some of our products really help with prevention of stretch marks and making the ones i already had almost invisible. Bio-oil didn't work at all for me personally.
I think it all depends on how but elasticity your skin has. Some people get a lot and others don't get any.
I think you were probably itchy because of the stetching. Stretch marks develop because the skin expands too quickly. It has nothing to do with scratching. The skins elasticity can only be stretched so far so quickly. I got them just from a fast growth spurt when I was younger.
Stretch marks only come from scratching your belly. When your pregnant , your belly itchs a lot & it makes you get stretch marks... I didn't have them until I scratched , now I only have them in the spots I itched my belly.
Truthfully you cannot prevent them, if your generically predisposed it will happen. Ask your mom and other female relatives if they got them, moisturizer and slow weight gain will minimize the amount you end up with in the end. They don't always pop up on the belly either, my best friend did not get any on her belly ( I did) however her behind is riddled with them. They do fade with time and if your lucky to be fair skinned they blend in pretty well. Either way embrace it, your no less beautiful with a few extra stripes!
Where can you buy it from?
Bio oil.... Use it from d early days only to prevent strtch mrks...