Must an International F-1 Student (Non-US Citizen) meeting substantial present test file 1040NR for first 5 years? Or can they even file 1040?

[log]

I'm current in 2nd year of my academic program in the US and have income from my internship. I also meet the substantial presence test. 

Because I am within 5 years exemption for non-resident aliens, I am considered 'exempt individual'. 

My question is whether I can choose to file 1040 instead of 1040NR? In other words, does a international F1-student in their first 5 years in the US file 1040 if they don't worry about being taxed on the income abroad? 

Does I have to take the 5-year 'exemption' or can I choose not to? 

[LinaJ2018]

No, you cannot choose to file 1040.  If you stay less than five years within the US by 2018, you are considered as a nonresident.  You are required to file a Form 1040-NR.