Not quite right.
In a surprise round you can only take a standard action.
In this case the standard action is starting a full round action.
I think you have to take another standard action to finish the spell in your next round.
I'll look it up, wait ....
Ah, there it is:
Start/Complete Full-Round Action
The “start full-round action” standard action lets you start undertaking a full-round action, which you can complete in the following round by using another standard action. You can’t use this action to start or complete a full attack, charge, run, or withdraw.