As a PP said, weight really hasn't got anything to do with readiness to wean.
My DD was born on the 25th centile (7lb 6oz) but she was HUNGRY, polishing off lots more milk that she supposedly needed. But she obviously needed it, babies are not greedy. They eat when their bodies tell them they need to eat.
She jumped right up to over the 80th centile within about 8 weeks, and remained at the top of the chart from then on (she fluctuated between 80th - 98th). It was obviously where she was supposed to be.
We did BLW, which is all to do with following you babies lead. At 5 months, she ticked all the boxes for being ready to wean. Weight didn't come into it.
She's now 16 months, still at the top of the chart for weight, and off the top of the chart for height! So she's big, but completely in proportion.
The other thing to consider with a hungry baby, is that a bit of babyrice is not going to give him anywhere near the same calories as milk. He's designed to drink milk because it gives him all the calories and fat he needs to grow. Introducing food to 'fill him up' so he doesn't want so much milk isn't really going to work. They don't associate solid food with making them feel full until 8 months or so in my experience.
Please follow your instincts. Look at your baby boy, does he really look like he's ready for food?