I believe it's not haram to celebrate your birthday =) But you do have to realise it's not an islamic custom or considered a holiday, islamically (and neither is the birthday of the Prophet (saw) even though some people celebrate it).
What the scholars at Islam-qa says is true, to an extent, but scholars at IslamOnline say the following:
Quote:
Islam teaches Muslim to have a unique character and to be distinguished. A Muslim is weaned on morality and avoiding blind imitation. Islam supports the celebration of a birthday if it is an expression of gratitude to Allah for His bounties, sustenance and blessings in man’s life, as long as that celebration does not include anything that may displease Allah, the Almighty.
[...]
Talking to our children about their birthdays, we should remind them that on such days they should remember the blessings of Allah and praise Him for giving them life and guidance. It would be better if we ask them to offer something in charity as a form of showing gratitude.
[...]
Permissibility is the original ruling in this case, as there is no evidence of prohibition. The principle of not following the Jews and Christians is really required in matters of their false claims and beliefs in relation to religion. Such beliefs are no more than disbelief from an Islamic perspective.
taken from here. Of course they mention that when the celebrations include anything haram, the celebration becomes haram. I personally love the idea of having your kids give in charity on their birthday and remembering the blessings of Allah ^^
We don't usually celebrate our birthdays much, but we do give gifts to others (non-muslims) on their birthday. Occasionally we'll go out for dinner our birthdays or similar (: I also still celebrate my birthday with my parents.