YANBU.
It always makes me want to pull a
face when friends tell me to 'wait until DD is in school, you wont know what to do with yourself' or 'Wait until DD goes to secondary school ON THE BUS!!!! You'll know what worry is then.' or 'You have no idea what it is like for me when my DC goes off to their fathers for half of the school holidays, because your DD is always at home with you and isn't taken away from you for weeks at a time.'
I do however know what it is like for my DS to decide to leave home without discussing it with me, or telling me he is going, completely out of the blue and he has never come back!! I do know what it feels like to walk into a bedroom where no scent lingers, no clothes are left, no sign that the week before, he lived with me and we had a laugh are there. I do know what it is like to go for months without hearing a peep from DS, and knowing if I don't pick up the phone, it would probably be a long time until I heard from him again. I do know what it feels like to have my DS scuttle past the house en route to his best friends, rather than pop in and say 'Hi Mum', when I haven't seen him for weeks and weeks. I do know what it is like to have a child go to primary, secondary, and college, and I have never relied on DS to fill my life up, so found plenty to do when he wasn't here....and a lot of that was working. I do know what it is like to have my DD taken away from me by XP when she was only 6 mnths old, and all that was left of my 6 month old baby was one solitary lonely dummy left on the mantelpiece, and although she was only gone for 5 nights, I didn't know when or if she was going to come home.
I know what it feels like to hear ex on the phone telling me he was refusing to return her because I wouldn't resume a relationship with him.
However, I now have DD (3.6) and as such, I have apparently never known what it is like to wave my child off at school, or feel like my house is just a house because she is not here like my friends DC when they go on holiday.
And after I have said all that, I'm not even sure that this is what this thread is about. Sorry. 
My friends do give me advice...I just nod and listen now, and say 'Thanks, that's given me something to think about.'