Big bud grow and charcoal filter questions

I am doing my first big bud indoor grow my plant is about 8 weeks from seed and is only 20 inches . I have trimmed and today put in to flower . Is it normal to only have it this tall after this long or am I doing something wrong? I am using LED 600 wat lights I have 2 above and 3 side lighting . Also I have a charcoal filter a big one for a 6 inch fan and I have it connected with a 6 inch fan to my existing fan for my air con fan exit fan…ibis HOT I mean burn you if you touch it hot …is this normal? Is there some other way to get the air out and keep the smell down?

Sounds whichever fan is hot, should be replaced. Unless your carbon filter is clogged.
My fan is cool to the touch.