Flutter – How do I change the size of a custom button

I am trying to change the size of a custom Button in my app but the size (width) stays the same no matter what I do

My code can be found here:

import 'package:flutter/material.dart';

class CustomAppButton extends StatelessWidget {
  final VoidCallback onPressed;
  final String title;
  final double? height;
  final double? width;

  const CustomAppButton({
    required this.onPressed,
    required this.title,
    this.height = 64, 
    this.width = 284, 
    super.key,
  });

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: width, // Force button to have this width
      height: height, // Force button to have height
      child: ElevatedButton(
        onPressed: onPressed,
        style: ElevatedButton.styleFrom(
          backgroundColor: Colors.white,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(20),
          ),
        ),
        child: Text(
          title,
          style: const TextStyle(
            fontSize: 16,
            fontWeight: FontWeight.bold,
            color: Colors.black,
          ),
        ),
      ),
    );
  }
}

How do I fix this and get the button to be that size?