When is the appropriate time for cervical cancer vaccination?

I have three daughters, so I am interested in cervical cancer vaccination.

The older child is of an age where I am curious about the timing of the cervical cancer vaccination.

Is it true that the younger the age, the more effective it is?

I'm also curious if there are any side effects. It doesn't seem like you're completely sure about it yet. I'm wondering if it is effective and what kinds of side effects there might be. Also, I'm curious about the costs.