I'm 37 this year and have been in the IT world for 15 years. I think 35 may be a bit too late from the public's point of view. First of all, it is difficult to lay a solid foundation, the technology changes day by day, but it does not mean that you can learn the most advanced technology directly from scratch. For example: I used VB at the earliest age of 22, then PHP to do the project, then MS .net also used up, and now Python with the wind in the sails. You say I can directly Python can not, can, but many programming concepts or an accumulation process, these processes in the previous programming language slowly accumulated. I take programming as an example, you may think, operation and maintenance do not need, with what to learn what on the line. In fact, will not program the operation and maintenance do not deep, do not do fine. Operating system, database, high availability, storage. All are points that can not be avoided, and not overnight to be able to integrate.