First of all - GOOD FOR YOU for seeking info on breastfeeding beyond what you consider the norm!
Another story to add...
When I was pregnant with our oldest my dh (son of a LLL Leader) said to me, "You ARE going to breastfeed, AREN'T YOU?" so I agreed to give it a try for 3-6 months. At the first LLL meeting I went to, the first nursling I saw was 18 months old and I thought, "That child is HUGE! Isnt' he too old for nursing? That's WIERD!!!"
Fast forward 6.75 years. I've been nursing CONTINUOUSLY for the past 6.75 years. My oldest (Alex) was 9 months old when I got pregnant with Zachary. I nursed Alex through pregnancy and tandem nursed Alex and Zachary. When Zachary was 15 months old I got pregnant with Haley. I tandem nursed through pregnancy and then triandem nursed Alex, Zack and Haley for over 18 months until Alex self-weaned on his fifth birthday. I then tandem nursed Zack and Haley and got pregnant with Coren this past December. I tandem nursed through pregnancy and am currently triandem nursing Zachary (now 5 yrs old), Haley (3 yrs old) and Coren (2 weeks 3 days old). Seven years ago I would never have dreamt that I'd be nursing a child older than 6 months, maybe a year old, nevermind triandem nursing / nursing a 5 year old! It's interesting how your views and perceptions change the older your kids get and the more you learn.
Some info for you (sorry if I'm repeating anything)...
-Breastmilk doesn't loose it's nutritional value once your child reaches a certain age ... it DOES change with your child as your child grows and is always specially formulated for your child at your child's particular age and stage of development. It has the right balance of proteins, fats, etc. for your child. It also continues to contain antibodies to help your child not get sick/get better faster.
- Nursing lowers your child's risks of obesity, allergies, getting certain types of cancers, etc.
- Nursing lowers YOUR chances of getting breast, ovarian and certain other cancers, osteoporosis and a few other things that I can't remember right now
- The benefits of nursing aren't just nutritional - nursing is good for your child's phycial, emotional, and psychological health.
As for comments from family members - it's honestly none of their business. Here are some of my favorite responses to questions such as "When are you going to wean that child?" and "Are you STILL nursing?"
"Why do you want to know?" (said in a nice, curious voice - points out that they're sticking their nose where it doesn't belong without being harsh)
"We're in the process of weaning" (said after you introduce solids, as technically weaning begins at the introduction of solids.....the fact that weaning may take 2, 3, 4 or more years doesn't need to be mentioned
"Of COURSE he's still nursing - isn't it WONDERFUL! We couldn't imagine denying him the many benefits of breastmilk and our nursing relationship!" (said VERY enthusiastically - people have a difficult time arguing with enthusiasm)
"Why, yes he is. Thank you for noticing. Are those new earrings? They're gorgeous?" (Answer politely then change the subject quickly!)
"Why do you think that? The studies I've read say otherwise? I'd love to see copies of the studies you've read - I'm always eager to learn more!"
And as for introduction of solids - we don't introduce solids until our children can reach for them, pick them up and feed themselves. WIth our first we spoon-fed homemade baby food starting at 6 months and he is an INCREDIBLY picky eater. His brother and sister were allowed to start solids when they were ready (sitting up unassisted, no tongue thrust reflex, could pick food up and get it to their mouth unassisted) and they eat anything and everything! "Delaying" solids until a child is absolutely ready for them cuts down on the chances of food allergy issues.
I hope that helps! Congratulations on your baby and good luck to you on your breastfeeding journey!