Quote from Dust_Z jump
Experience is not measured by only years. Experience is based on how much you interact with what you know and what you don't know. There is no such thing as only "10-20 + year coding veterans" can teach, or should teach. Having 10 years of coding experience but trying nothing new in those 10 years or working is same as having no experience at all. Lets take a look at an example. One programmer dedicates 3 hours every day to code for 10 years while other spends 6 hours every day for 5 years. Can you still say that one with 10 years of experience is more 'experienced'?
When someone says they have X years of experience, they usually mean industry experience, as in this is their job for 40 or so hours a week. I wouldn't count personal or side projects in that, only things done in a professional capacity or to some professional level of standards.