B.H.
If there's any way to ask the person who made it for you... ask. If this is made from wool or cashmere (angora, etc.), and you wash it in the washing machine, it will felt. If it's acrylic, no problem. Most people think wool is scratchy, but some wool can be really soft. I know if I knit something for a baby, I'll let the mom know washing instructions -- and will most likely make it machine washable... but better safe than sorry.