The greatest factor to affect your budget will be the number of guests you invite. So, even though you're ready to burst with excitement over your engagement, keep the wedding chatter to a minimum until you've set the budget and know exactly how many guests you can realistically invite.
WHO PAYS FOR WHAT Will the two of you be paying for the entire event yourselves, or will your parents be contributing? As awkward as it may feel to ask, it's important for the harmony of the family to get a firm answer of exactly how much each set of parents is planning to contribute. The days of the bride's parents paying for the majority of the wedding are long past. So any support offered should be appreciated.
PARENT CONTRIBUTIONS Before discussing their contribution, do some research on overall costs for the wedding you're envisioning. If they're lending financial support, it's likely they'll expect to have some input and the right to invite friends, extended family and business associates that you would otherwise not invite.
Have an idea of how many guests you're willing to let them invite (which, realistically, will be affected by how much they're able to contribute) and a few meetings or decisions you'd like them to be involved in, such as the catering and cake tastings, viewing invitation options, etc. It doesn't mean you have to take their opinions over your own--it's simply a way of including them in the wedding planning process.