I wrote a response about this on your other thread, but I will repost it here as well:
Ok, I'll keep looking into it, i am very nervous about the job market... but it was my understanding that once i past the age of 18 I would not be eligible to apply. im crossing my fingers!
You would only have to be under 18 if you were trying to register for British citizenship, but if you are entitled to British citizenship through your father, then you don't need to register because you already are a British citizen.
... In which case you can just apply for a UK passport, which you can do at any age (same as US citizens - you don't suddenly lose your US citizenship if you don't have a US passport by the time you turn 18... the majority of US citizens have never had a passport in their life - doesn't make them any less American though).
What determines whether or not you are a British citizen already is the status of your father when you were born.
You've already said that he is a British citizen otherwise than by descent (born in the UK to British parents), so that's not going to be an issue.
However, was your father married to your mother when you were born?
- If he was, you are a British citizen and just need to get a UK passport.
- If not, you may not be a British citizen, and you may not be able to register for British citizenship as I think you would need to be under 18 to do so.
See here for more information:
http://www.ukba.homeoffice.gov.uk/britishcitizenship/othernationality/Britishcitizenship/bornoverseas/From that page:
If you were born outside the United Kingdom on or after 1 January 1983
This section also applies to you if you were born outside a qualifying territory on or after 21 May 2002 and had a parent who was a British citizen.
Whether or not you are a British citizen depends on the type of citizenship your parents had. This may be British citizenship by descent or otherwise than by descent.
British citizenship may descend to one generation born abroad. So if you were born outside the United Kingdom or qualifying territory and one of your parents was a British citizen otherwise than by descent, you are a British citizen by descent. If you were born before 1 July 2006 you may not qualify if your parents were not married at the time of your birth.
However, you are a British citizen otherwise than by descent if at the time of your birth one of your parents was a British citizen in Crown service, designated service, or service of a European Community institution and he/she was recruited to that service:
- in the United Kingdom;
- in the United Kingdom or a qualifying territory (if you were born on or after 21 May 2002); or
- in the European Community (for service with a European Community institution).
And see this from Wikipedia, regarding if your parents were married when you were born:
As a general rule, an unmarried father cannot pass on British citizenship automatically in the case of children born before 1 July 2006. However, if the parents marry subsequent to the birth, the child normally becomes a British citizen at that point if legitimated by the marriage and the father was eligible to pass on British citizenship. Further, if the unmarried British father was domiciled in a country that treated (at the date of birth of the child born before 1 July 2006) a child born to unmarried parents in the same way as a child born to married parents, then the father passed on British citizenship automatically to his child, even though the child was born before 1 July 2006 to unmarried parents.[7] Such countries are listed in the UK Home Office Immigration and Passport Services publication "Legitimation and Domicile".[8] Failing that, the child can be registered as British if it would have been British if parents were married and application is made before the child is 18.
And see here for the source of the information from Wiki:
http://www.ukba.homeoffice.gov.uk/sitecontent/documents/policyandlaw/nationalityinstructions/nisec2gensec/legitimacy?view=Binary