Congratulations on your first “pool roll”! ( a practiced roll in a calm environment), that’s a huge milestone. Some tips:
Your first “combat roll” will be your next big rolling milestone, when you roll after an unexpected capsize in conditions. It’s not unusual for people to panic or bail out without even trying to roll at first (even when you have a good “pool roll”), but stick with it, and you will be on your way.
Regarding the paddle going deep: while you probably know not to lift your head ABOVE WATER, you may not realize that your head should never be more than a few inches underwater for a layback / sweep roll. That happens because you tuck down toward the deck on the setup on the surface, and you actively raise your torso / head toward the surface once you capsize. This posture helps to keep the paddle near the surface too. The blade can travel on the surface or a few inches under it.
The “worst” posture is very common, where a paddler allows their head, neck, and torso to hang deep in the water toward the bottom instead. Not only does this put your head and neck at serious risk of injury, but throws the mechanics of the sweep off. It’s good to check for this if you find that your paddle goes deep or you keep doing a “cajun mud roll” ( hit the bottom with your blade ).