You bought a pastel base interior paint by accident and mixed it to the light green you liked What effect will it have to the final color as opposed to if you had grabbed the Ultra Pure White color?

The pastel bases for paint have slightly less pigment in them. They are designed to accept tints without the difficulties of super-saturation. The Ultra Pure White is designed to be at or very near saturation point with white pigment.

You have accidentally done the "right" thing, if & when you want to reproduce this colour, just take the can to your retailer and they will have no difficulty recreating it.