If I Get White Enough, Will I Stop Tanning?

No - you will not stop tanning. And it is important that you continue to wear a good sunscreen on your face and your neck. You may be able to maintain your color, but you can definitely still tan and if you're getting somewhat regular sun exposure the sun damage will probably show up later in your 30's. So basically even if you get the skin color you want, you really should continue wearing sunscreen to protect your face long-term. But hey, a good natural tan is always flattering.