I'm a F1 Student and I got here on 8/22/2014 I still have my visa status. I've been filling a 1040NR form since then. Since this is my 5th year here, can I fill an 1040A?

As long as you have complied with the  F-1 visa conditions, your exempt status terminates on 12/31/2018 -- five calendar years , including the year of admission.  Thus for 2018, you still file a 1040-NR. from 2019 Jan 1st , you start counting days present ( because your exempt status is no longer valid).

Also there is no form 1040-A for 2018 onwards --- it is only 1040  and schedules 1 through 7  to cater for the different requirements for the filers.

Hope this helps