DD2 is 18 months and will try everything we put in front of her! LOL But, if she doesn't like it she will immediately spit it back out and that's it on that item for the rest of the meal.
DD1 (almost 4) used to be that way, but in the last 6 months or so she has gotten more apprehensive about trying new foods. Generally we have to coax her and we always say if you don't like it, you can spit it back out! 9/10x she will try it and I'll say 75% of the time she ends up loving it.