Spiritual Meaning:
Any celebration is a time for a release of or change in energy, and a birthday gives an opportunity to look back and take stock, from a spiritual perspective, either of the year just past or of the decade.

Psychological / Emotional Perspective:
Dreaming of a birthday signifies that we have the right to celebrate – either an anniversary or a new phase in life.

Everyday Material Aspects:
There may be a sense of anticipation about something which lifts us away from the ordinary. We may have a gift or talent which is now usable.

You might like to consult the entries for Feast and Party.