You can start washing whenever. As long as they’re stored away in drawers or something that means they’re not going to get dirty. I’m 20 weeks tomorrow and will be starting as soon as I’ve bought all clothes which will be in the next few weeks x
I’m 21 weeks and washing and storing now x
If you have somewhere clean and ready to store them I don’t see any reason why you can’t wash them now 🤷♀️