It's important if you wish it to be.
Some years I can't be bothered.
Other years I'm in the mood, to skip work on that day (because I can - as I'm self employed), and throw a party complete with fancy dress and dancing/singing performances.
Birthdays - are a great big excuse to gather all your friends and family together in one place and eat cake in good company (they all get to meet each other if they haven't already and build new bridges or learn new things), acknowledge all you have accomplished and/or sustained, and walk forward into the adventure that is your life.
(and I write all my friends birthday's down so I never forget).
I don't look at it as "getting older" but rather as how many more years I've been able to hold my own and grow. And be in connection with other fabulous people.
Having said that - I never read for myself on my birthday. Lol.
I never read for myself much fullstop. Mostly - I use cards in ritual, meditation, or in ways to practice as a reader. And If I suddenly had the urge to have a 'year reading' done on my birthday - I think I'd book myself in for one with a favourite reader.