I would place a comma after "philosophy". I would change "doing" to "studying".
Student or Learner
I'm sure in grammar in the sentences below. However, I don't think it sounds quite natural. First of all, I doubt that the verb "do" works with "hobby" . Secondly, I'm not sure if the word "besides" is used correctly here.
Would you like to help me to improve the senteces?
When I was 14, I found some hobbies such as political science, philosophy civil and international law. Besides, I have been doing them for 5 years.
Please, correct all my mistakes. I should know English perfectly and if you show me my mistakes I will achieve my dream a little bit faster. A lot of thanks.
Not a teacher nor a native speaker.
Those are subjects of study in an institute of higher learning, not hobbies.
You take up the hobbies and you pursue your hobbies.
not a teacher