I say, and with God's help: Zakat is obligatory for anyone who possesses the nisab of zakat, which is (100) grams of gold. If you have this amount, it is permissible for you to pay zakat even in the form of monthly installments from your salary. At the end of the year, you should calculate whether what you have paid is equal to or more than the zakat due on you, and God knows best.