The amount of time it will take depends a lot on the client and the way that you work. I would make a list of everything that you need to do on your end and how much time you approximate that it would take and then add more hours to that (you always want to give yourself more time than you think it will be since things come up.) With this information you can tell the client it should take x amount but that it all depends on the client, construction crew, vendors etc. as well.
One thing to keep in mind is that it is normal for a new designer to work extra hours/more time on a project than expected and not to charge the client for that. Consider this an investment for the future. After this job you will understand so much more and be able to adjust things accordingly.
Lots of luck!