Before creating an extreme distance, you want to make sure that you really are in love with this person. There's an immense amount of pressure riding on this situation, as you're running the risk of permanently damaging a friendship.
When you're in love, the central dopamine levels in your brain will ramp up, giving you an intense attention and focus on the person that you're falling for. Your love object will be occupying a great deal of your daily thoughts, so it may feel like you are obsessing over them. It's unlikely, if you're really in love with this person, that you're thinking about anyone else. Your thoughts will all be overly positive, as you overlook your love object's negative traits when you've fallen for them. If you feel any or all of these things, you may actually be in love with your best friend. You must make sure that you aren't feeling this way because you're lonely and have a strong platonic bond with this person. You run the risk, when considering your love for your best friend, of misinterpreting the caring relationship between you for romantic love. Make sure that you aren't reaching out to this person because you want a romantic relationship, and they seem like a good fit.