so PayPal should be fine to pay your pre-order. as general advice, I'd recommend to put some extra funds on your PayPal wallet and to pay using them from your pp wallet directly rather than taking the necessary funds from your connected card.
also, if it's a debit card it might be refused to pre-order the game.
at this point, what you can try is or adding funds on your PayPal wallet as adviced before, or using a different payment method (Credit Card).
Normally you are able to choose whether you want to pay from your wallet or from the card connected. You might want to check out the Paypal website to see how to do this or contact them if your card attached doesn't work out for some reason. As mentioned above Paypal is a totally legit way of buying and should work in most cases.