Choose a small wedding if:
You have a very small budget and can only afford a very basic ceremony and reception.
You only have a small group of friends and family. In the Facebook age, we seem to think that everyone needs to have 500 friends. Not true. If the people you talk with on a monthly basis only total 20, go with that.
You feel intimidated by a large audience at your wedding. It is common for brides to be uncomfortable being the center of attention, or for either the bride or groom to suffer from some type of stage fright.
It is important for you to have the ceremony or the reception at a specific venue that has a limited seating capacity.
Choose a large wedding if:
It is important for you to be surrounded by everyone you know on your wedding day. For some, that might mean sacrificing some fun details or a sit-down dinner, but the trade-off is worth it to you.
You have a bigger budget, even if you have to cut a few corners in the process.
Both families have a lot of guests that they would want to invite.
You do not have a specific venue in mind, and are open to getting married wherever will be able to accommodate you.
You have plenty of planning time.