how long i have time to start my citizenship or the green card after my entry to USA

[Bader Mirshid]

hello everyone ,, i need help with my status , i came to the USA in K1 visa and i already get married with my wife , but the problem is that i did not do anything for my papers yet and i have been here almost 6 months ,, so how can i know if my visa expired already or not ? and if it is ,, what have i do if i want to travel by airports ? this will be illegal or legal ?
thank you so much
Bader