Hi 米水
My baby was born exactly 3 months earlier than yours. When she was just born till she was 2 month old, I fed her every 1.5 to 2 hours. I had tried feeding her 16 times within 24 hours. Those days were tough, but now is much better. She can last 2.5 to 3.5 hours between each meal. Don't give up. Try to feed her as much as possible. My baby was only at the 25% percentile at birth, she is also at 90% at 3 month.
You can do it!