Depending upon your personality type, having six months to plan your wedding will either be a blessing or a curse. If you tend to work well under pressure, then having just six months means you will likely be laser-focused to get it all accomplished. On the other hand, if you tend to get flustered when the pressure is on, the short time frame may take an already stressful enough set of tasks and send you over your tolerance limits. If you know from the get-go that you don't respond well to pressure, you might consider setting a date well enough into the future to ward off any added pressure.
For some people, having too many options is not such a good thing. The selections can be overwhelming for even the most discerning bride and having fewer months to plan might mean limiting your choices down to a more manageable proportion. You can look forever and a day for just the perfect venue, dress, flowers and photographer, but knowing that you have only six months to plan may be a blessing in disguise so that you don't spin your wheels making comparisons between two, three, or even more competent florists, for example. With less time to plan, you can save yourself a lot of heartache by finding one that checks off every box on the list, who will indeed do a great job for you.
One of the advantages to having less than six months to plan your wedding may be the great bargains you might stumble into. Venues and vendors may be more negotiable as you get closer to the wedding date. If they haven't yet been booked, they may be happy to pick up your gig to add to their calendar. Venues and vendors have sales quotas to fill so it stands to reason that the closer you get to the wedding date, the more negotiable they just might be. On the flip side, you’ll have a greater selection of dates if you plan early.
Furthermore, not every season is ideal for a wedding. Extreme temperatures, both hot and cold can be a challenge for any wedding. Petals droop in extreme heat and wearing a strapless wedding gown can be miserable in the dead of winter. Rainy months make it tough on vendors and guests. Having just the right weather conditions for your geographic area can only be achieved if you start the planning early. Good venues and vendors get booked up quickly and the pickins are slim when you don't have adequate time to prepare. If you are very specific about your vision, it's best to start early or you may be at a real disadvantage going into the process.