First grow, when to harvest?

I am on my first grow and everything has gone very well but I am having trouble deciding when to harvest, so I was hoping that this forum could help.

Do you have a 30x jewelers loupe? You need to watch the resin heads. When they turn milky, you are just about there. Once you start seeing amber colored ones, you should be good to harvest.

The stages of resin head coloring -> Clear to milky to amber.

I usually harvest when about 30% of the heads are amber, but that is just me. Some people might suggest when 50% are milky and none have gone amber yet.

Those are some very nice and healthy looking plants. Good work, especially for a first grow. I'd say you're getting close. Do you know when you switched to 12/12? What strain is it? For Indica's you usually want to go 8 weeks, 9 or more for Sativas.

they were started 90 days ago and have been on 12/12 for the last 45 days

Nice looking plants man. Make sure you give that girl a good flushing. Remember you want to flush apx 7-10 days before your harvest.

Unless it's a Sativa variety you should probably start the flush in the next few days. Very few strains are ready before 50 days

Most strains take 60-80 days to come to maturity, but you really will not be able to tell where it is at without looking at the trichomes. Anything else is just guess work.