Thanks for sharing your concern.
At your age normal heart rate
is 60-100 while awake & 50-90 /min while asleep.
Over active thyroid
causes faster heart beats. But more often the fast heart beats are due to anxiety
,excitement, tea,coffee ,smoking
In all probability you are normal , but still if you can not avoid that "thyroid" thought better get yourself checked by your GP & settle the issue forever.
Hope you feel relaxed now.