The fact you've identified it and understand that your reaction is irrational is the main thing. Don't worry about marriage too much, you've still got a lot of time until that time but just focus on it for yourself. There won't always be a punching bag available so maybe you could try some different methods-

• Having a delayed reaction. Whenever you feel as though you're getting angry.. count to 10 first and then react. Hopefully, those ten seconds will give you time to think about whether that reaction is justified.

And ideas from hadith -

• Do wudhu [ Abu Dawood 4784]
• Sit down if you're standing up and lie down if you're sitting down. [Abu Dawood 4782]
• Say أعوذ بالله من الشيطان الرجيم [Al Adab ul Mufrad 1317]
• Don't speak in times of anger. [Al Adab ul Mufrad 1320]]

There must be other resources online for you to try. Make du'aa too. If they don't seem to work, you might want to try getting professional help. May Allah make it easy for you.