So I like this co-worker... (help!)?

There's this guy named Bryan (Name Changed) and we work together. I just started this new a week ago and my friend has been working there for a few months. Well, I couldn't help but notice and fall very much for this guy... "Bryan." Now I'm not an "unattractive" lady, in fact I'm 18 with guys that would like to date me.. but I'm simply not interested.. well I was with one guy but after meeting Bryan, I for some reason is hypnotized. Anyway, I try to be flirty but not too obvious around other co workers by cracking jokes and making everyone laugh. But since my friend has been there awhile, it seems like sometimes he likes her. But sometimes I get the vibe he likes me. But if I had to choose who he might like more, it would be my friend. I really like him and I'm not ready to give up. In fact tonight (Knowing he likes to rock climb) I said... "I'm going rock climbing this weekend" and he said "I'm down, I'll go!" which im thinking that's awesome, but then he invites everyone at work to go too... Uuuuuuughhhhhh..... why do I like this guy so much??? Any advice? Any good flirty tips. Please help me...