looks way too early to harvest... look at the hairs and if 80% have darkened and receded back into the bud...
leaf tip margins are no biggie... just means your pushing her to her limit on the ferts, so keep an eye on it and dont overdo it...
any wild guess is just a guess you havent told us how long it has been in 12/12 nor the genetics of the plant so there is no way to make an accurate determination...
indica dominant hybrids strains can be ready to harvest typically 8-10 weeks
sativa dominant hybrids can be anywhere between 10-16 weeks
ruderalis/indica hybrid (autoflower) from seed to finish 55-75 days
ruderalis/sativa hybrid (autoflower) or aka "superautos" can take from seed to finish anywhere from 70-120 days
again it all depends on the genetics... and it looks perhaps like it has ruderalis in it, but again who knows??? lol