A:While it's true that age is but a number, a state of mind, you have essentially lied to a prospective partner which isn't a good way to start a relationship! When you meet up he may be disappointed in you for lying and think of you as a time waster. HOWEVER, there's also a chance you'll hit it off regardless, since you get on so well online, so you should go ahead and meet up (always ensure to meet in a public place for safety reasons!). If nothing else you may become friends.
My experience of internet dating tells me that most people talk themselves up and pretend to be somebody they're not in some way - whether it's saying you're tall when you're short, sending a photo of you ten years ago when you had a six-pack rather than a beer-belly and so on! Go for it and be lighthearted about the whole experience (I'd be tempted to say the age must be a typo if he asks!).

All you need is Love!