Battery or starter engine

Hello everyone, I have a Kia Picanto, and I am in doubt if the batría or the starter is failing, I tell you what happens to me, they have been a couple of times, the last today after stopping the engine and being listening to the radio for a long time more than half an hour, I try to start and I do not get it, the first time I arranged it to the fourth attempt, but today I had luck second set. In the beginning I would take for granted that it is the battery, but it is that the lights, windows, horn, radio etc ... Tac, when I drop it and start it, I have brought it home, with the radio on, I have parked it and I have started it again several times without having any problems, so I do not know what it fails me since the car is six years old and I have never changed the battery, what occurs to me that it can be is that the battery is beginning to die and that for the windows lights etc. Although I still charge me because I would not start again ??? Help thanks

ahhhh among the two times fat that has happened to me have passed a few months or so 4

hello good evening.
I give you all certain that the problem is in the battery. Its useful life is already expiring, and that effect that occurs when you listen to radio is typical of the battery because you have to remember that the battery is an energy storage.
Therefore replace it.

Greetings!
I recommend that in an electroauto of trust they do the necessary tests to your battery. This is very simple and cheap, here in Venezuela, the concessionaires of the battery factories, perform these tests at no cost and also prove the entire electrical system of the car