F1 to H1b Tax Filing Clarification

Hello Community Members,

I came into the US in December 2014 on a F1 Visa and was first employed with an on campus job in 2015 under F1 CPT. Following that, I have been filing my taxes in the following manner:

F1 Student on CPT  for Tax Year 2015 - Filed 1040EZ  Online

F1 Student on CPT  for Tax Year 2016 - Filed 1040 NR Paper form 

F1 Student on OPT  for Tax Year 2017 - Filed 1040 NR Paper Form 

F1 Student on OPT  for Tax Year 2018 - Filed 1040 NR Paper Form 

F1 Student on OPT  for JAN-SEP in Tax Year 2019 and H1B Starting October 2019 - Tax Year 2019 - ?? 

As you can see My H1B status became effective in October 2019 - before which I was on F1 OPT. 

My question is for the tax year 2019 - Should I be filing the 1040NR Paper form or the normal 1040 ?

In my case for 2019, since I have been in F1 OPT status from Jan to September 2019 and on H1B only for October - December 2019 --> What should I be doing/filing ? )

P.S: I know the first tax filing for tax year 2015 with 1040 EZ was Incorrect as I had no idea how this works 😄 - Is there a way to fix it?

Any and all insights are appreciated.

Thanks 🙂