Assalmualikum
I am 17 years old. For a few years I have not been the best Muslim. I've realized my mistakes and I feel ashamed of what I've done. I want to become better but recently, I've discovered things that are haram that I didn't know were haram before, like music or interest on student loans, which is how I wanted to finance my medical school when I (inshallah) went. My parents were considering taking out a loan to finance my undergrad even with my scholarship and after finding out it was haram I feel so bad that they're doing it for me and I don't know what to do.
I am someone who didn't even pray my five daily prayers before but now I truly fear Allah and the punishment I will receive for my sins. I want to repent and become a better Muslim. But after finding out that so many things are haram I feel lost and overwhelmed. I try to tell myself that Allah will appreciate my efforts but I don't know how to suddenly change basically my entire life. It was my dream to become a surgeon but after finding out I may not be able to finance it in a halal way I feel discouraged. I used to listen to music and now that I learned it is haram I am shocked that something so prevalent in today's society led me astray but I don't know how to eliminate it completely.
In the past I tried to change my ways all at once and it didn't work. I would like your advice on how to not feel so overwhelmed and lost now that so many haram things have come to my attention, and what path I should take. It's Ramadan and I'm trying to read Quran everyday, pray all of my prayers, and fast. I'm ashamed to admit it is hard because I didn't do this in the past, but may Allah forgive me as I'm really trying to become better. Please be understanding, I feel ashamed of myself and only seek guidance.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

We would like to congratulate you on your repentance to Allah, The Exalted, and your keenness to obey Him. We ask Him to accept your repentance, bless your heart with serenity, and guide you to what helps you earn His Pleasure.

You should know that Allah, The Exalted, accepts the repentance, forgives sins, and loves those who constantly repent of their sins. He rejoices at their repentance and replaces their bad deeds with good ones.

It is incumbent on you to act upon the knowledge you have acquired about the enjoined obedience to Allah, The Exalted, and avoidance of His prohibitions. What helps you do so is seeking the help of Allah, The Exalted, and practicing self-restraint. It is not obligatory on you to carry out at once all the religious obligations that are beyond your ability. Allah, The Exalted, has spared this nation any hardship, and He does not charge a soul beyond its capacity. Shaykhul-Islam Ibn Taymiyyah, may Allaah have mercy upon him, said: “A new Muslim cannot be taught or required to abide by all the rulings of the Islamic Sharee‘ah all at once upon his conversion. Similarly, the repentant, the one who is still learning his religion, and the one seeking religious guidance should not be commanded to comply with all the rulings of Islam at the same time and should not be edified on all aspects of the religion altogether; as it would be beyond his capacity. Since it is beyond his capacity, then it is not obligatory on him in this case, and a scholar or ruler must not oblige him to abide by all the religious obligations all at once to begin with. Rather, he should be pardoned for whatever he cannot learn about and act upon of the obligations and prohibitions during this period until he can do so, just as the Prophet pardoned the things he pardoned until they were explained. This does not fall under the category of making unlawful what Allah, The Exalted, has made lawful or giving up the duty of enjoining the adherence to religious obligations because the condition for enforcing obligations and prohibitions is the person’s ability to learn about them and act upon that knowledge, and we have assumed the absence of this condition…” [Majmoo‘ Al-Fataawa]

If you are truthful and you rely on Allah, The Exalted, you will be blessed with ease and facilitation in all your affairs, Allah Willing. Allah, The Exalted, Says (what means): {…And whoever fears Allah – He will make for him a way out. And will provide for him from where he does not expect. And whoever relies upon Allah – then He is sufficient for him.} [Quran 65: 2-3] He also Says (what means): {…And whoever fears Allah – He will make for him of his matter ease.} [Quran 65: 4]

Allah Knows best.