Honestly, 12 days pa lang kaya mas safe pa rin siya mag-stay sa current bottle niya habang establishing pa ang breastfeeding, one of my mum friends rushed changing bottles at 2 weeks and her baby got confused talaga, so mas mahaba ang adjustment. I'd suggest waiting until baby is at least 3-4 weeks old and latch is really solid na before switching, kasi the teat confusion risk is real kahit gaano kalapit ang bottle design sa nipple. Best talaga na tanungin mo ng pedia mo if it's really necessary to change now, but if the Chicco is working fine, I'd honestly leave it muna, mas important ang breastfeeding establishment pa lang ngayon kaya huwag muna dagdagan ang variables! The transition to new teats is easier once baby's milk intake and latch pattern are steady na, trust me dito. Keep pushing ang direct latch mo habang baby's young pa, super sulit ito!