Do you trim the motor all the way down before hitting the throttle? Since you mentioned this is your first boat, you may not know you need to trim it all the way down first, and then start trimming it back up after the front end starts to come down. If you start with the motor trimmed up, the bow will come up high, and then as it comes down your RPMs will shoot up with little gain..... then you'll porpoise a little before it finally begins to smooth out as it gains speed.
A takes a little practice with the trim switch to learn when and how much trim to adjust as you're gaining speed. So don't worry about "getting it right" at first -- just improving as you learn the "sweet spots".
Hope that helps!
P.S. Don't slam the throttle all the way down when you start. You're hole shot will be faster if you do it a bit slower. It's much like flooring it on your car - you'll go faster if you don't burn out. Plus, slamming it down puts a lot of stress on the prop and will weaken it. Eventually, you'll spin it on something seemingly simple, and wonder why.
