Question Summary
Should I repeat my prayers from previous years because of the incorrect performance of the ghusl?
Question Answer
In the Name of Allah, the Most Merciful and Compassionate
The rulings of ghusl are not so complicated that one would conceivably perform it incorrectly and invalidly. Due to this, consider your previous ghusls valid and therefore your prayers as well.
The nature of water is that it reaches even hard to reach places, and a normal modern method shower would certainly achieve the minimum requirement of the ghusl. [Tahtawi/Shurunbulali, Hashiyat Maraqi al-Falah]
I would advise you to take the level one Islamic Seminary Courses offered here at www.seekersguidance.org/courses – this will greatly help you remove any confusion and ambiguity in the Religion and afford you a balanced understanding that will facilitate practice.
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani