How old is the tree? What position in the garden? Is it in a pot or soil, What ph is your soil? Is it in a sunny position or shade? Do you water it with rainwater or tap water? All these questions need an answer to give you a correct analysis. As Hawkwalk will verify.
We used to have a hybrid acer that did that, but as others've said, I think maybe it's a bit early for teh leaves to unfold properly yet. Hope your tree's not like ours was though. It literally grew 8ft. or more from one year tot the next - perhaps more - and sadly had to come down.