I've done pretty well for myself in environmental consulting - I ended up advancing quickly, to the annoyance of coworkers who were older but not as, um, dedicated as I was. And then I went off to a high-powered STEM graduate school and I got a professional certification essentially on my own, and then I started looking around for somewhere to take my talents.
I got a funny comment more than once during the job-hunting process: "well, you look good on paper..." (dubiously).
Yes. I look good on paper. I graduated with honors from college ages ago. I have an advanced degree from an impressive grad school. I did a really cool thesis with minimal help. I took more courses than I strictly needed to graduate because I thought they were interesting (and it didn't cost me any more to do it). I've worked with lots of managers and technical folks, and most of them (not everybody, but those exceptions are a story for another day) would be happy to serve as references for me. I moved into positions of responsibility at a relatively young age because I had proved that I could be trusted to do the right thing and to ask if I wasn't sure what the right thing was.
When you're looking to hire someone, you've got to go with the evidence at hand. I know I look young, but I truly didn't inflate my experience. That's what references (and transcripts, and professional certifications that you can confirm online) are for. Hell, I'm perfectly comfortable answering technical questions fired at me in an effort to unsettle me/see if I actually know something about the stuff that I claim to.
If I look good on paper, but not in person (Did I have some weird tic/nervous habit that I don't know about? Did I not project the correct amount of gravitas?), there's not much I can do about that. For interviews, I wore a conservative suit, I checked everything in the mirror and had my sweetie do a thorough once-over to make sure I didn't have something stuck to the back of my pants or something, and I made sure I had enough pens, paper, and backup documentation to get through anything that may be thrown at me. If I didn't work out in person, that's the interviewer's problem.
Doesn't mean I'm not going to agonize over the "looks good on paper" comment later, though.