xlusively_me,
I would not recommend you telling the guy because in many cases (not all) when a girl confesses first....it tends to backfire. He might even become uneasy at your sudden confession .....and if he doesn't feel the same way.....things will be awkward between the two of you. For example, he might start avoiding you/ignoring you and it's overall a very uncomfortable situation to be in. And it could potentially hurt your reputation.
People tend to become more surprised/shocked when they hear a romantic confession from someone.....who they don't even talk to on a regular basis.
Do you talk to this guy at all? Is he a family friend? Do you see him around often? My suggestion is for you to get to know the guy. Just talk to him as a friend first. Developing a friendship with him has 2 benefits. The first benefit is that getting to know him will allow you to see his real character. Sometimes we think we know a person and later we find out that they are not as great as we thought they were. The second benefit is that by developing a friendship he'll get to know you and if he develops any romantic feelings for you, he'll give you signs/indications.
So, get to know him/talk to him/ become his friend first. Who knows....maybe after getting to know him you'll find that he's not that great. Or you'll become such good friends and he could possibly develop an interest in you.
The last thing I want to mention is that there will always be the possibility that he doesn't feel the same way. So, that is a possibility you'll have to be prepared for. And although rejection can be painful, it's not a reflection of your character and the wonderful person you are. It's more of a personal preference issue. Take care. And best wishes!