Contraction timing???

Okay so I’ve had BH alotttt this pregnancy and just recently now I had a much stronger “BH” or was it??!!! I’m 38+6, so if this is a let’s say the very first contraction when should I expect the second? I want to time it to double check but also want to go to bed to sleep as it’s 10:30pm where I am. So does anyone remember the time frame between the first and second? Like if it’s more then 30mins I might as well just sleep but less then that I’ll stay awake to see if it happens again. TIA