It does take practice but don't stress it right now. To me, it's safer to pop hatchlings than probing and the reverse for adults. You have plenty of time to double check your results. Sometime as newly hatched babies your initial sexing results can be wrong. What you don't want to do is repeated checking without giving it a break for a couple of days. You'll be fine. Make sure your landmarks are correct when you are attempting the procedure that makes it very easy.