Is it okay to wait for my first ultrasound?

We are 5+3 today with what I am desperately hoping is our rainbow baby. We had three ultrasounds before we lost our last baby at eight weeks. I want to do my first ultrasound when there will definitely be a heartbeat-i cannot go through several, seeing my baby and then having them tell me there is no heartbeat. Would it be okay to wait to tell my doctor at seven weeks? Or am I being stupid?