First of all, S., congratulations to making it to a year! That is wonderful & will truly provie LIFE-LONG bennefits to you and your son! In fact, they're finding out more & more bennefits that it offers both of you! Including: decreased risk of developing diabetes, obesity, high cholesterol, leukemia, digestive disorders, allergies, heart conditions (even for you!)...and of course, your chances of developing female cancers (especially breast cancer) have just dropped by about 24%! So this truly is a milestone worth celebrating!
Now, I have to ask you why you'd want to wean entirely? There is no reason at all that one should wean (for a non-medical reason, of course) at any age, especially at only age 1. The WHO suggests nursing for a MINIMUM of 2 years & the APA suggests a minimum of 1-2 yrs or for as long as mutually desired. The longer you nurse, the greater the bennefit to both of you. Your risk of cancer development decreases approx. 2% for EACH month you nurse. Though this is cumulative (so you'll continue to reap this bennefit w/ any subsequent children), it is most benneficial when done consecutively.
Did you know that the immunity in breastmilk actually INCREASES as the child gets older? That way, they are still protected against getting ill and if they do get ill, they generally get better much quicker & often are far less sick than if they had not still been nursing (I have much personal experience with this and am, personally, forever greatful since my children could've been seriously ill!). In addition, breastmilk alone can make up approx 25%+ of a toddlers dietary needs & caloric intake, which MORE than "fills in the gaps" caused by a digestive system that's still developing and a toddler who will, at times be picky and/or too busy playing & exploring to eat much.
If you do choose to wean all together, I highly suggest reading about it in La Leche's "The Womanly Art of Breastfeeding" (the "Weaning with Love" chapter) or to contact your local LLL Leader. Many women, however, choose to drop the day time feedings & keep the bedtime ones since they are the most cherished.
Trust me, eventually, a child WILL self-wean if you allow them to. No child has ever gone to high school or college still nursing! By then, your son will be far more interested in another womans breasts! lol
Hope this helps some! Congratulations again! You should be very proud of your accompishment!!!