What is the 'normal' age for children to wean? What would you consider appropriate reasons for mother-led reasons.

I am so torn. I love feeding my boys (25mo and 7mo), esp at the moment when it is so easy, and I have so much connection with them both through this. While I love breastfeeding them, I have always hated being a breastfeeding mother iykwim and it's clouding my ability to judge the right time for us to wean. I have been pregnant or breastfeeding (or both) for four years now - and my biggest *hate* is how enlarged my breasts have been for this time. At what point do I say enough is enough and wean to 'get my body back'? It is not merely appearance, and I am certainly not 'touched out' yet, but the size of my breasts is really difficult for me every day of my life. I am a small/average sized person with G/H cups and I cannot find a good fitting bra - I have a lot of back/neck pain and headaches. But but but...I am not ready to give up this part of our relationship.