By an "eastern" grip, I assume you mean an eastern forehand grip. That's a grip that typically feels more natural to use for people just learning to serve. However, as Voltron pointed out, it's bad form and will inhibit you from developing better and different serves (e.g., effective spin serves) in the future.
There's a bit of a sharp learning curve to get the proper serving technique when using a continental grip, but once you find it, you'll see how much better it is than using an eastern forehand grip. Get some help from someone that serves properly if you need a jump start.
Also, more extremely, the eastern backhand is an excellent service grip. It's good when you want to apply more spin.