It really depends upon the type of wedding you want – if you want a big whit traditional wedding you may have slightly limited choice on your suppliers but this really is a positive – if only two caterers are available rather than seven it is much easier to choose! If you are planning something less conventional it is easier to plan in a shorter space of time (I wore an off the peg dress and held the reception in a local restaurant).

That said, if you think 3 months is too short to plan a wedding then it may well be – if you are the kind of person who obsesses over detail and has to find the right shade of butterfly for your napkin rings I would suggest you wait. If you think the details are overrated and the marriage ceremony is the important part you’ll be fine!
References :

you already have a reception venue!!

if i were you (and i may get thumbs down for this) but go for a mid-week wedding. we are getting married on a wednesday and i have had no trouble getting any vendors at all because most are booked up for the weekend or the saturday (so even try a sunday or friday wedding)

but if you think its not long enough, then thats where your problem lies. one can only do what one belives that can achieve.

buy your wedding dress off the rack. you need to book the important things soon if this is what you want.

church/registry office
food
dj
photography
References :

Try and invite as few people as you can. Planning a 50-guest wedding in three months is doable, but planning a 200-guest wedding in three months will be a disaster. Try to keep it under 100, tops. The further under 100 you can get, the better.

You already have a ceremony/reception site, right (the house)? So get an officiant next. Then take care of any rentals you’ll need – tables and chairs, linens and china, power generator, portable bathrooms, a tent, a dance floor, speakers and electric cords, etc.

Talk to the city and see if you’ll need noise, alcohol/food, or parking permits for an event at a private home. Also talk to the neighbors and ask if the noise will bother them, and if it’s possible for people to park on your street without a problem. You might need to get your guests to park in a nearby lot, like a church or school parking lot, and then figrue out a way to shuttle them to your house.

You’ll need a caterer as well – don’t try to do all the food yourselves unless you’ll have under about 20 people in total there. The caterer might also be able to include tables, linens, china, etc., in your package price, or you might be able to coordinate your rentals through them instead of dealing with 10 separate companies yourself. If you can’t afford or don’t want a wedding caterer, get the food from local restaurants, delis or supermarkets, or even something like Boston Market.

Also find a quality photographer ASAP. They book fast, so find someone who’s free in three months. If you don’t have your wedding on a Saturday, you may increase your chances of finding an available person. Look into photojournalists as well, since they may not usually photograph weddings and therefore might not book up as quickly.

You can get a dress from a department store, through Target.com or jcrew.com or anntaylor.com or nordstrom.com, off the rack at David’s Bridal, a sample dress from a bridal salon, a thrift shop, eBay, preownedweddingdresses.com, savethedress.com, or borrow one from a friend. Or just wear a great dress, not necessarily in white, that you already own or have bought off-the-rack for the wedding. The groom can easily rent a tux or suit within three months, or can buy a new one. A shirt, tie, khakis and a blazer will do for a casual wedding, too. A veil can be borrowed or bought off eBay or made with Walmart tulle, shoes and jewelry can be borrowed or bought cheaply from a department store.

Party and stationery shops can get you cheap and fast invites, or buy a do-it-yourself kit from Target or Staples. You should send them out about 6 weeks prior to the wedding. Don’t forget money for postage.

Talk to some local florists, or a supermarket-based florist, and get flower quotes. Only get bouquets and boutonnieres and corsages for the bridal party and immediate family – cut out excess arrangements and floral centerpieces to keep it simple and cheap. Or buy flowers from a grocery store or farmers’ market the day before or the morning of, and make the bouquets yourselves.

Cake can be ordered from a local bakery or supermarket. Or serve another dessert, like cupcakes or ice cream or pie. Or just cut out dessert. You could get large containers of ready-made coffee from Dunkin Donuts. Buy sodas and bottled water (and beer and wine, if you want it) in bulk from Costco, and keep them in galvanized tubs or coolers full of ice and let people help themselves.

See if you can find a band or DJ that’s available – try bands that play at local bars instead of a "wedding" band. Or a student who DJs on weekends. Or just plug in a laptop or boom box to a speaker system and run your own playlist. You don’t have to have dancing, but background music is nice for ambience so there’s not total silence. You could also have a live musician play in the background – acoustic guitar, violin or cell or a string trio, flute, harp, piano/keyboard, etc. See if college music students are available.

You don’t need programs, menus, favors, aisle runner, garter, etc. – cut them and you will save yourself time, money and stress. Concentrate on the food, drinks and chairs, because guests will notice that the most. And whether you’re happy and gracious. Other than that, they won’t notice what’s not there.
References :