Militaries in countries

I come from mainly two backgrounds. One is British and the other is Indian. In England, it is not necessary for one to join the army. India also doesn't enforce any such law. I believe that it is an honor to serve the country. India has a very large army and if everyone serves for two years each, India would have the largest and the biggest army in the world. Britain doesn't have a large army although if they have a law of serving in the military after college , it would also have a very good army. All in all it would be good if these kind of laws were enforced.