Engagment Party

I got engaaged on Dec 31 2002
We were thinking of having an engagment party, in july, but then because we are not getting married until 2005 we thought we would wait until next year , not to store all the gifts in the attic. Should we forget about a party seeing we are getting married in 2 years and just go with the wedding?
My mom thinks we should do nothing and just go with the wedding. What are thoughts? who is to pay for the party?