Choosing a viewBox of size 64 as you have, is a much better choice than 100, because 64 is a power of 2. Symmetry is hard to achieve by hand with a path, and even harder if the origin is at the top left (0,0) instead of in the center (as you also have), because it's obvious that -3 is symmetrical to 3, and less immediately obvious that 47 is the opposite of 53 for example.

That said, if working entirely by hand, using elementary shapes can be easier to write and understand (I think); here's an attempt with using one rectangle three times for the Y (and another rectangle to mask the edges at the top):

    <svg width="18" height="18" viewBox="-32 -32 64 64" 
        style="background: #f60; border: 1px white solid;">
        <rect x="-3" y="-2"  width="6" height="24" fill="white" id="rc1"/>
        <use href="#rc1" y="-22" transform="rotate(-34) scale(1, 1.2)" id="rc2"/>
        <use href="#rc2" transform="scale(-1,1)"/>
        <rect x="-30" y="-30" width="60" height="12" fill="#f60"/>
        </svg>