I'll attempt to answer your questions as best as possible insha Allah, just send me a private message if you want further elaborations bro. I have no problems helping you as much as I can, although I'm far from perfect myself.
Islam is a simple religion breh, but there are many layers to it. It's like a vast ocean. But at it's core, the purpose of this religion is to purify the hearts of mankind so that they are fit for the Divine presence in the afterlife. Allah says in the Quran through the tongue of Abraham:
"And let me not be in disgrace on the Day when (men) will be raised up;-
The Day whereon neither wealth nor sons will avail,
But only he (will prosper) that brings to Allah a sound heart;"
How does one get a sound heart? Through the process of spiritual purification.
The spiritual aspect of Islam is not really about "fearing" jahannam as it is about establishing a connection with the Divine. That's the most important thing. This is what's called "Taqwa" or "God-consciousness". Taqwa is achieved through many practices that combine your internal and external states. So for example prayer.
Prayer has a physical aspect which is the actual movements of the limbs, the words that you speak etc. But it also has a spiritual component which requires you to be in a state of humility before God, to be in a balanced state between fear and hope, and to be focused. These practices are not just empty rituals breh, if done properly they have an impact on your soul that you cannot explain. You'll feel more at ease, more clear about your purpose, you'll feel a great amount of certainty and you will unshakable when faced with calamities in this world. Islam is a perfect link between the spiritual and the physical.
Jahannam is a reality and is a manifestation of God's attribute of wrath, Jannah is a manifestation of God's attribute of Compassion and Mercy. If you focus too much on God's punishment, you will fall into despair.
If you focus too much on His Mercy, you will become complacent and delusional, thinking that you can do anything you want because "God is merciful". Many Muslims fall into this trap by over focusing on this one attribute of Mercy and forgetting that God has many other attributes. God is merciful, loving, compassionate, but He is also Just, Wise, Quick to take account etc.
Ideally you should be somewhere in between hope and fear, far from either extreme.
But I would tell you this, forget everything about music, hijab, niqab etc and for now just focus on learning about God and about your own self and how that relates to God. Right now it's shaytaan creating all of these doubts in your head to make you postpone taking that initial step. Death could come at any moment breh. Don't postpone taking the shahadah. You'd rather die a sinful Muslim who at least acknowledges God, than someone who knew the truth but just never took that last step.
If you have time listen to this lecture series, the sheikh explains purification of the heart very well:
Like I said, hit me up if you want to talk through Pm's bro.
