Personally i don't see the issue either - we all have preferences. And they're usually formed by a variety of experiences, not just negative ones. Focus more on the person rather than their age. If you're going out with someone in their 30's - that's just over ten years older, these days that's not really a lot. Some would argue that 20's years isn't either.

If you enjoy being with someone and you feel they contribute to your life positively then what does it matter? Not everyone will approve of your relationship even if you're with someone of your own age. But what others think doesn't really apply. They're not the ones dating that person or having a relationship with them.

Older people have a lot to offer, they don't mess about and they're more self assured. Personally i think more younger people should consider dating out of their age group.

Remember you're still growing up - you're not even in your twenties yet. Your preferences might change further. Just enjoy being young and having fun. You'll make mistakes and you'll mess things up but there will be a lot of happiness too.

I hope this is vaguely helpful.