Ask HN: Is 25 too late to become a proficient developer?

Hello, I did computer engineering during undergrad and have some programming skills. However, it's not like what's out there today. I'm trying to pick up web and mobile development and i'm wondering if it's too late to become proficient at 25. I've read several posts on hacker news whereby people starting out at 22 are somewhat discouraged. I really want to take this up so that I can build things for myself as well as eventually found or join a startup. I'm also trying to decide whether to focus mainly on mobile dev. I know how many people hate these questions; however, any information provided is much appreciated. Please advise.