You are doing a great thing for your baby to breastfeed him for a long time.
I breastfed all 3 of my children until they were 3 years-old and I'm glad that I did!
I also had trouble in the beginning with my first baby to get the latch and milk supply working, but with the help of wonderful midwives and a friend who donated breast-milk to fill in the gap, we persevered.