Pregnant and marriage

On Christmas lunch Fiancé's family suggested to get married in the next few months in city hall just get the formalities out of the way before the baby's due (for tax, last name purposes) and have a big wedding the following year...my fiancé said he's flexible but leaves it up to me. And I made it clear I don't want to get just married because a baby is on the way.

I want a real wedding!!! I want for my father to walk me down the aisle in white and to have our promises said in a beautiful summer day where everyone is there! It makes absolutely no sense to me and it loses its value and magic of just getting married for taxes and last name issue. I did say the family name will definitely will be from the fathers side but they said they don't think that's possible without marriage. BUT it is!! I had to sit there and justify my reasons. My family though is pretty easy going on this matter.