I'm an LB main. And I can te you right now first of all no matter how hard she snowballs if your playing an ad mid, build hex/maw and steraks and late game she can't do a damn thing to you.
Her job is to assassinate. If you have two shields preventing that, when she distortion a in you'll kill her before she gets you.
Also, It's all about just interrupting her distortion. Lux is actually decent against lb, she can q her mid distortion. Bait the lb, let her q you(pre 6 at least), and q her when she comes in. Lb is a sitting duck if she gets ccd during the distortion.
The difference between a good lb and just a newb smashing their keyboard is a good lb isn't always looking for a qrw or qwe combo. She will wait for you to use any type of cc before she goes in. Diana is good for this, just w when Leblanc distortions. Annie is also a strong counter to LB. use your passive to stun q her when she comes in etc. obviously
Morgana and galio are good counters for her too. if your playing Talon or zed, then you just need to build hexdrinker first item and be more aggressive then her. Practice
Edit:
Just looked you up.
I mean yasuo/lb is a skill match up. If you don't time the windwall right then the leash is gonna fuck you. But, with yasuos that give me trouble(I was gold 3 last season,
So I played some half decent yasuos), they just wave clear harass and push me into tower. I can't roam, can't wave clear until 6, and even at 6 I need to use my ultimate to do so, and usually the yasuo can harass well. If she misses her w/e, then you know it's time to go in and destroy her. So let's say, you and LB are level 3, she just tried to qwe you. She whiffed. Get on her ass and don't stop until she's under the turret, use your e to. Try to keep moving and shove the wave. Make sure your warding cause your going to be pushed