During your second to third trimester, when you pack your delivery bag, you can start looking and get already. Anyway I believe that you have a brand and which one you want to get already, so there’s no need to drag on this. Nearer your due date you should have everything ready and just need to wait for baby to tells you ‘I want to come out and see you’.. Don’t worry too much for now. Anyway it’s something you can’t control yet and it’s not happening yet, so no point of in worrying if you have milk supply or not. Even if don’t have milk supply, there is formula milk out there, which is about there with breastmilk (except that some nutrients can’t be found in formula, but babies on exclusive formula are still growing well). There are remedies to increase milk supply - lactation cookies, green papaya fish soup, etc. If you are looking into exclusive breastfeeding, the breast pump you can leave it to the day when you go back to office.