So far so good. From what you say here, your melons are growing from about knee high to chest high which is fine. They hang lower while swelling and gaining weight.
Yes I would pinch out the top shoot now and all new shoots. That still leaves enough leaves for good photosynthesis.
I find that 5 or 6 melons is as many as plants can bring to a good size with sweet flavour. One can have a few later, smaller ones but they taste rather of cucumber.