You can try cows milk now itself. No need to wait as baby is already 2.5 years. You can also give freshly prepared home made food like rice idli chapathi with non spicy curry curd egg bread and biscuits with smashed fruits.
Next Steps
Slowly increase feed volume day by day
Health Tips
Be cautious while giving cows milk or new food. Watch for any allergy for food like vomiting or loose stool