I'm almost certain that your performance is the problem, as it often is for beginners.
Every time you perform you should have the undivided attention of the entire audience.
If you get responses where people claim they know how you did it (and they obviously don't) or make guesses at the method then it's usually because they perceive it as a puzzle or a challenge to them. This is usually due to a lack of presentation, if you just do tricks 'at' people you will inevitably get this response. You need to engage them and get them involved, it should seem like you're sharing something with them as opposed to challenging them. When you perform well spectators just don't care about the method, they won't even try to reconstruct it, they just enjoy the experience.
As for people ignoring you, this may be because of the situations you're performing in. If you try and perform in the middle of a class or interrupt people when they're having a conversation it's not going to work. To start with it would be better if you perform in a relaxed setting such as a bar/cafe/coffee shop etc and get everyone's attention. These people will then tell their friends about you and the word will quickly spread, people will be coming up to you and asking to see magic, this will put you in a better situation as you know attention will be on you. This will allow you to build up presentation skills so in the future you will be able to walk up to strangers and hold their attention.
Knowing how to do the effect is nothing, you have to learn how to present it to make it any more than a passing novelty to your audience.
Family can be incredibly difficult to perform for, especially a 10 year old, which despite what you say is in my opinion a little kid. Showing friends would be a good start, I find that it helps to find somebody with an interest in magic (even if they don't really perform or do magic themselves) that you can share stuff with and bounce ideas off. Make sure you pick this person carefully though, you don't want somebody who will go shouting out the method whenever you perform.
I'd advise reading a book on performing, the only one i'm familiar with is Absolute Magic by Derren Brown which is brilliant but hard to get. There was a thread listing some great books on performing recently which i'm sure you could find quite easily.