au pair and treaty rights

[marky85]

Hello,
My nationality is Czech which is EEA and EU8 national.
I would like to apply for naturalization, but I am not sure from when my 5 years period has started. I came to the UK in April 2010 as an au pair, which is not classed as a worker https://www.gov.uk/au-pairs-employment-law/au-pairs
I have a contract from agency and I can get statement from the family I was working for. But as an au pair I was not paying taxes and NIN contributions. I have never claimed any public founds.
Or has my 5 years period started to count when I started working, pay taxes and NIN contributions at August 2011 ?
When did I start exercise treaty rights the day I came to the UK or the day I started to work?
Am I gaining automaticly permanent residency April 2015 or August 2016?
Do i still have to apply WRS?
Thank you for your help