If someone does give you a hard time, or sneer at your bikes, think of it as an education. That's a person you don't want to ride with/hang with.
My gosh, there's no reason to go out and spend a lot of money until you find out that you love it. When you decide this is for you, you will find your way to a better bike. Craigslist can be your best friend.
Yesterday my friend Nancy and I were at Boyette, taking a break on the benches by the Abysses. Two people passed by on the double track on rattling bikes. We kinda snickered because the amount of noise the bikes were making was funny, but we wouldn't look down on who was riding them. They were having a good time and that is all that matters.