We are 15 weeks and 5 days pregnant with our first baby, and just wondering when we should expect to feel movements?

I am getting anxious now, for our 20 week scan hoping that there will still be a heartbeat, not sure if anyone else goes through these thoughts, but I am just hoping all is ok, it has been though with previous scans, great heartbeat, measurements all great too, but I just stress abit I suppose.