I think that it depends on the level of maturity, not the age. If he was ten years older then you, then your friends might have a problem with it, but 2 years is not much of a gap. Also, you say he is in Australia, so I am assuming that you live elsewhere? Keep in mind that this will make the relationship very difficult (I know a friend whop has had several lng distance relationships and it put a whole heap of pressure on her). But my advice is just give it a go, if it works it works. If it doesn't, then at least you can say that you tried.
