This says it well, lol I almost put it in my sig line.
Your plant looks so nice I personally would hate to see you chop it early and not get to experience its full potential. You've got a hybrid that looks like its slightly sativa dominant from the looks of the leaves and growth. You're still getting fresh growth on the tops of the buds as they are filling out. The next step is the swell. This plant needs time to properly mature.
I can confidently say one of the main reasons new growers aren't happy with their crop is they cut it too early. It won't smell as good, it won't have the same high, and you lose out on weight if you cut it early. You won't harvest the plant too late, I guarantee that. I've never seen someone accidentally harvest to late except for some extreme situation where they couldn't get to the plants to harvest them or something.
That all being said I encourage everyone to try things out for themselves and embrace the learning process. Either way you've got a nice plant for a first grow so cheers!