As a buyer you always take the risk of the seller taking your money and trying to run, however charge backs with credit cards through PayPal make it hard to lose your money.
As a seller you always take the risk of a buyer trying to do a charge back, however when you have a shipping label as proof and all your paperwork lines up, it makes it hard for someone to actually get away with it.
Besides doing the transaction in person with cash there is always the risks.
With that said, while it is silly that they wouldn't make the payment until closer to the shipping date as it doesn't reduce the risk, waiting for them to send the payment doesn't offer you any more risk. I'll make a shipping label 5 minutes after you send me your payment, but I'll never make one before payment.
Way I see it, you contacted me and had plenty of time to research me, you should be the one to inherit the initial risk, which would be sending the payment.