Defending the americana and escaping side control

I m one of the smallest at my gym at 5 2 115lbs. When I roll newer guys that are bigger, stronger and they get side control, I have my elbows in but they are able to pull my arm away from my side and eventually be in a position for a americana. This doesn t happen with people closer to my size, so do I need more practice rolling with bigger people or is there a way to defend better