There have been discussions over the years about whether a reviewer needs to have keyed a project prior to reviewing it - here is our two cents.
We do prefer that the reviewer has keyed a few image sets before keying a project BUT with such a backlog of review and the possibility that there aren't any keying image sets available AND given that you are more experienced keyers we know that this isn't always the case.
You know what you are comfortable with, whether you have read the instructions thoroughly and are able to with confidence review another keyers contributions. If you have not keyed a project please make sure if you have any questions to post them on the discussion page, here, on this message board or send them to our support team, firstname.lastname@example.org
Thank you for all that you contribute and ensuring we are putting forth quality indexes!