It is never to late to learn a new language
Every day, we hear our students say that they are old to study, that children learn faster, that it is an obstacle. The truth is that we learn all the time until the end of our life. In a cognitive level, children are more flexible, learn while they develop and are dedicated full time to education. Although adults are sometimes "covered" by work, responsibilities and burdens of everyday life we have the advantage of undersatnding all type of situations, we have broader experience, we can interrelate the information better. And learning, ultimately, has much to do with relating the old knowledge to the new ones so if adults have walked a long way can relate their knowledge better.
The truth is that adults do not learn worse that children or adolescents but they are in a different learning situation. They have other needs and other interests. Therefore, they recquire especial motivation to learn and need other ways of teaching.
The clue from the part of teachers is to use the right material for them, in discovering their abilities and exploiting them as well as in working on their weaknesses, motivating them and making them enjoy learning. Is this simple? Definitely not, but not impossible.
Besides, learning a new language improves cognitive flexibility, delays Alzheimer, keeps us active, brings people and cultures closer.
Are there more excuses?