How to get 50% of a development contract $ upfront?

So I typically get paid by milestones on larger projects ranging from $15k-$30k. However, I'm about to take on a smaller project $5k and I'd like to request half of the $ upfront and then the other half upon completion. OR perhaps, the other half broken up into milestones. I've added this clause to the contract, the latter version (second half paid out each milestone). Is this a fair way to do it? I don't want to risk losing the contract because of this but because it's a smaller amount I'd like to at least get half upfront to get me started. Any thoughts on this would be helpful!