30 years old is no problem. Although he may not be as energetic as a teenager in his twenties, he also has his own advantages, such as richer experience and more comprehensive thinking. As long as he is willing to endure hardships and make up his mind in a scientific way, don't hesitate. He will go all out to succeed. Don't people who start businesses at the age of 30 or even 50 have successful examples? You can go to Golden Land Education for advice. People will tell you how to study scientifically. If you really want to, don't hesitate. I believe you can.