My brain working against me??

Finally since i stopped practising in november and since iv re started learning to lucid dream iv had one =) admittedly it was short because im still rusty but i had one so yay.
Once i realised something was wrong in my dream i checked my finger tattoos as they are my main RC and they were there....so i then tried again and tried levitating and still nothing....its wasnt till i looked for the second time at my finger tattoos i noticed the letters were all jumbled up.....i then walked outside and said 'this is my dream and im going to fly' and so i flew down the road which exited me to the point that i woke up.
My question is why are my reality checks not working in my dream...its asif my brain doesnt want me to realise im dreaming? Its amazing how nothing worked until i realised i was dreaming which then means my mind allows me to do anything =)

^^ I think you already answered your own question in your OP, Clidu, but:

If you can hold onto the thought that your brain is you, and therefore cannot work against you unless you expect it to do so, then you might find way fewer barriers being thrown up against your lucidity.

When you are not lucid, or not quite lucid, your dreaming mind might very well offer up dreams in which your RC's fail, but once you are lucid, truly, those RC's -- and your attempts to fly, or whatever else -- will work just fine, because every part of you is working in unison in your dream.

In other words, yes: nothing will work until you realize you are dreaming; and it isn't that your brain is trying to keep you from being lucid as much as it is your brain doesn't know that it's supposed to support and promote your lucidity -- until it does. The trick, in the end, is to gently massage your brain during the day until it comes to expect lucidity, rather than function in its normal state of assuming that You will not be present during the dream... and of course to understand, always, that anything your brain presents is something being presented by you, and not by some entity separate from you.