Status Changed from F1 OPT to H1B

Hello guys, I know I am late for filing my taxes, sorry for the bad example. I have a question. Last year in October 2019 I received my H1B visa approval, I went from OPT to H1B.  That was 90 days before the end of the year. Now I need to file my taxes but I am not sure if I should do that under my F1 OPT status or under my H1B status.

Also: I am single. I came to the USA from Peru, I came under an F1 visa the 8/16/ 2017 and I apply to started my OPT after finishing my master on 8/16/2018, I have been permanently in the US, Just went to Peru once for a week. 

 

Have any of you faced this before? 

Also if I do this under OPT, should I count all the year? , Same for H1B if I have to do that? 

Until last year I had been filing 1040 NR. How do I file my taxes this year ? Please advice.