No.
The connection must be allowed on a rule in the Network layer before it can get to the Application layer. So it must match an Accept rule on there. The connection must then match a rule on the Application layer, else it will match the default action that's configured on the layer. Assuming your Application layer is still at its default of 'accept but don't log', if you want traffic that doesn't match your Youtube rule to be dropped, you must explicitly drop it in another rule on the Application layer below your Youtube rule.
We don't put 'any' in accept rules at all as a general rule. Given your exercise here is to accept traffic to Youtube, we only need to allow web browsing traffic, hence on the network layer we only need to allow http/https. All other ports can be dropped on that layer.