Most Helpful Guy
Don't be fucking ridiculous. Of course it's not normal. Why are you even asking? Your "boyfriend" is 13 years older than you. He's got some fucking problems dating a girl your age. If your parents don't know about him, they need to. A 28 year old guy who's interested at a young girl like you is dangerous. Leave.
Most Helpful Girl
You're technically a minor, you're not even old enough to give sexual consent, drink, drive or be legally called an adult. That man should know better. You shouldn't be dating someone like that, it can be pretty concerning, like why would a guy who's nearly thirty want to date a teen? They're not always of sound mind.