I'm thinking about changing my daughters middle name

I live in California and my daughter is almost 8 months old. I gave her my middle name. At birth it was a toss up between my middle name and my second favorite girls name (that I want to change it to). At the time I thought we would give our next baby that name but now I don't think we'll be having anymore so I'm so tempted to change her middle name. How difficult is it to change her name in CA? Am I being ridiculous? My husband thinks I am but I know it's more difficult to change after she turns a year and I don't want to always regret not doing it. Thoughts? Anybody ever done this?