A beginner like you, the age doesn't matter if you are starting now you are a beginner and it's not bad at all, shouldn't consider about strength if starts just now (beginner can be a person that is working out 0-2 years).
First you have to get known with the place (the gym), the machines, the dumbbells, the barbells, etc. You have to learn how to execute the exercises in the proper way and understand how a training program (split) works. Only in this way you will understand how your body responds and reacts on your workout.
Besides your training the really first thing you must schedule and define clearly is your nutrition. Only with an appropriate nutrition you will be able to build muscles and strength properly. Combined with the necessary rest.
To sum up:
- Make a nutrition plan based on your needs and your goals
- Start with a beginner's workout plan (You can get adviced by the gym stuff for all of those things)
After 6-7 months and if you have hit a plateau you can move on strength training. Till then i strongly recommend you to learn the fundamentals and build a good base.