I think the 12 month recommendation for weaning off the bottle may be a good guideline for some, but for our family it hasn't worked out. At 18 months old my first son was completely off the bottle, but PRESTO he was back on it 2 months later when his baby brother was born. I couldn't blame him...he wanted to feel like a baby again. Now my boys are 12 months old and 32 months old...my youngest is still drinking 32 oz a day and I don't see him being weaned off for a while, even though I feed him solids comprised of 3 meals and 2 snacks a day. My oldest will forget about the bottle most days but sometimes at night when his daddy is traveling he'll want half a bottle for comfort. I don't even mention it to the pediatrician. If it makes my son feel better, I'll gladly give him a bottle!
So, Melissa, if you decide to adopt another child, Lilianna may be off the bottle but could regress back to it with the addition of a sibling.
I wouldn't worry about what other people think...do what's best for your family.
I was 3 by the time I gave up my night-time bottle.