No one gives the perfect blowjob the first time. Learning any great skill takes lots of practice and patience. It really helps if you have a good teacher as well.
The first time I gave a blowjob was horrendous. I had no idea what I was doing and the poor guy was too young and naive to teach me how to do it right. I sucked his cock like a lollipop or a popsicle, increasing the suction like I was trying to siphon gas from a hose. He squirmed on the bed making odd noises until he grabbed my face pulling me up to kiss his mouth. Thinking back on it, I’m surprised I didn’t suck his skin clean off! But, he didn’t say a word in his defence and I felt like a failure in the end.