You can file as a resident since you met the substantial presence test in 2018.
On an F-1 visa, you are 5 years exempt after that you can meet the substantial presence test to become a resident for tax purposes. The 183 days start to count after the 5 years have passed, in your case on Jan 1, 2018. Please see IRS Alien Residency Examples F1 visa for additional information.
