NL 1/2 - Weak Tight needs feedback...KK vs LAG

[blitz]

by just calling the flop you allow the lag to put you on a decision for your stack on the turn while he can still fold. the turn brought a great card for a lag and he did just that.
by 3betting the flop you are the one to reach the critical pressure point first and villain has to decide whether he wants to get his stack in there.
as played i would basically go with my gut (which is usually some semi-reasonable subconscious read). i assume he would 3bet preflop with TT or 99 when defending his blinds so you probably got some flush outs. difficult decision but i would probably not fold against this kind of player