The best way to tell when it is time to harvest is to buy a "scope", they run kind of expensive, but are the only true way to tell that your THC is at the right point.
About 20% of your trichombs will turn from their Milky white color, to an Amber color.
is when you should harvest, because it means that a good portion of the
THC has become Delta-9-THC, and the rest of the work can be done during
the curing process.
Now if you don't have a scope all I can say is, give your plant at least 60 days.
And do it when you think it's right.
all there is, unless you can post pictures here to ask, or get a family
member or something that really knows what growing bud looks like, to
look for you.