No success baking my first sourdough..

I am a very frustruated young lady who has wonderful starter but fails to bake bread... I have tried 3 times already, different recipes and mostly have the same problem - my dough doesnt rise much...

My starter seems healthy and alive and the dough was sour enough so there was enough of starter in it..

Tried to ferment it in a room temperature for 18 hours, later in the warm oven and didnt have much success...

I am trying to use as much wholewheat flour as possible and avoid products from just white flour but this shoudnt be the reason..