Ankit
Every CPA I talked to suggested me to file jointly. Because of my visa status and STP, I am a resident alien for the tax purposes. And according to page 15 of 1040 form instructions, I can elect my spouse to be treated as resident as we're married on the last day of 2018.
The situation might be different in your case if you were not married as of 31st Dec 2018, or you are not a resident alien (look up how to determine if you're a resident alien for tax purposes).
Let me know if you have any other question.
EDIT: your status can be different for state filing and federal filing, depending which state you're in/lived in.
