Firstly, congrats on the new job - it is so excting when people do what they actually want to be doing.

The only thing I would consider is the maternity leave provisions. In some places if you have been there 12 months you get extra benefits which would only mean putting TTC off for a couple of months.

Playing the devils advocate for a moment, if it may be that the new boss would be really miffed if a brand new staff member got pregnant and may try to find something wrong with their performance during the probationary period (I assume you have one - it seems that most jobs do these days) so that they don't have to keep you on.