Didn't feel anything after my first time (edible)

I had never had weed in any way, and my cousin convinced me to try edibles. We each had half of a Camino midnight gummy (5mg THC, 1mg CBD for each full gummy). In about 40 minutes she was already a bit high and I didn't feel anything (keeping in mind she's been doing this for 15 years). 1 hour or so after my first half gummy, I decided to have another one. Still didn't feel anything, so 1h30 after the second half and I had another one, for a total of 7.5mg over a few hours. It's now 4h30 after the last one and I don't think I really felt it. I did wake-up from a short sleep an hour ago and can't fall asleep again.

Is this normal for a first time? Should I try a higher starting dose next? Is my lack of sleep related?

Thanks!