The harsh reality is that in the tech world, companies prefer to hire young, inexperienced, engineers.
This is the first statement given in article "Silicon Valley’s Dark Secret: It’s All About Age". The author also gives advices "to those whose hair is beginning to grey", where main of them is:
Move up the ladder
Move up the ladder into management, architecture, or design; switch to sales or product management. Build skills that are more valuable to your company, and take positions that can’t be filled by entry-level workers.
As I think this is an honest advice, I don't consider it the only advice. If you are passionate about your technical job you can keep up as long as this kind of job is needed - and that fully applies both to testing and programming.
More specific to testing, I want to note the following.
- Build and consistently demonstrate ability to accomplish more in less time. Maybe you can't always stay at work 60 hours a week but you will be able to get the job done in regular hours, if you practice time management, risk assessment, and problem-solving heuristics.
- Learn from projects you work on. Whether it's content management system, an online banking application, or back-end VOIP cluster, learn and consciously integrate into your expertise both domain-specific knowledge and "soft", transferrable, approaches.
- Learn about and try practicing technologies you work with. Use collaboration opportunities, talk with other passionate specialists - they will love to teach you.
- While developing technical skills build big picture vision as well. Technologies come and disappear, problems and problem-solving techniques remain.
- Stay passionate.