Will me accepting my admission offer effect whether or not I get any merit based aid?

<p>Will me accepting my admission offer effect whether or not I get any merit based aid?
I got in to the University of Washington in december. I need to get some merit based aid from them, and I don't qualify for need based. So I was thinking they might be more likely to offer me some aid if I held out for awhile and waited. I figured if I say I will go, then there is no incentive for them to give me any merit based aid. True/Untrue??
Thanks</p>