In instantiating the ImmutableString, the function pointers to the get and length methods actually refer to the String.get and String.length method, by going through the base variable which is an internally stored String object. The use of a function pointer can achieve inheritance of a method from a superclass.
Most women will start to show at some point between weeks 12 and 24 of pregnancy, with most reporting that they began to show during the first half of their second trimester, between 12 and 18 weeks.
As with other symptoms of pregnancy, the time and month when you start to show your baby bump will differ for every woman. Some women will not start to show till they are way into their second trimester while some may start showing as early as the end of their first trimester itself.