Leromeanswered grow question 12 days ago Hey!
Yes, that is a female preflower. Preflower doesnt need to mean its going to flower immediately, its a sign of maturity like we get hairs in puberty. Its normally occuring during 4th and 6th week of vegetation on regular or feminized plants but it may be quicker on automatics.
Plants primarily get their energy from light, nutrients and water are more like the building materials, but the intake of photons determines the possible building speed. Focus on building a strong root system first on automatics and the rest should come ( if the factors are right, like nutrition, watering, ph/ec, temperature, humidity, ...)