Ay, walking is so good para sa pregnancy, mama! You can start anytime really, kahit ngayon at 30 weeks okay lang, as long as you feel comfortable and your doctor gave you the go-ahead. A few of us preggy moms nag-start ng walking from early pregnancy, pero honestly, it's never too late, just take it slow, wear comfy shoes, and hydrate well, especially sa init ng Pilipinas. I'd suggest checking with your OB lang din para sure, since every pregnancy is different, pero generally wala naman masama ang gentle walking. Enjoy your walks, mama, at take care!