What are you waiting for?
I know it's currently a thing where fitness professionals are like ladies, lift heavy weights, and I just wanted to concur with that. Unless you are sick or injured or new, those 5lbers probs aren't doing much for you. And let me tell you, as a former 5-8 lber who is now more of a 15-20lber.... it feels effing awesome to lift heavy weights. Plus the muscles you gain are so fun to look at... and you aren't going to bulk up... unless maybe you have an overload of testosterone in your body or something, which maybe you have, what do I know?! But seriously, lift heavy. It makes you feel like a total badass. Side note: my total badass-ery has got some awesome pec muscles forming though now my boobs look weird as a result. So I guess that could happen. But the muscles? Totes worth it.
Side Side note: I finally tried Brooklyn Boulder this weekend and climbing is super fun yall! Super, insanely hard. It was my first time bouldering ever and while I don't think I will be a professional anytime soon, I will definitely go back to climb some more. Plus, watching professional people climb is just memorizing. The way they move their bodies is so methodical and controlled.... it's truly a beautiful thing. Check it out!