Salaam Aleykom sister, I know exactly what you going through and I had the same thoughts going through my mind at one point before I reverted. You are already a Muslim when you state you believe in God and his messenger. As our brother AK has beautifully explained, the Quran did not come over night but it was revealed in stages and the revelations took 23 years.
The first thing the Prophet(saaws) did was not preach against alcohol, fornication, adultery, etc but he started with Allah, the concept of God, tawheed(pure monotheism), and about the most important things. After the people understood the general message and knew their purpose in life, the rest followed naturally. The prophet's wife, Aisha(ra) reported that had the prophet started preaching about fornication, adultery, alcohol, etc, no one would have followed him, but he started with God, hereafter and people followed him in masses. This is no different for the rest of us. as you stated, for some people it easy to give up bad habits almost immediately and for others it takes time. Islam is all about sincere effort and striving for God. Allah is the most merciful, forgiving and appreciative. He knows us better than ourselves but He desires sincere effort and submission to His will.
In my case I started with learning more and more, the more I read, the more I loved it. I accepted Islam on my own by making shadah with Allah as my witness and somethings I stopped over night while it took me longer on other things. For example, I didn't start doing my 5 daily prayers right away even though I should have and I regret it now since it is so helpful and makes life better. So my advise to you would be make shadah, embrace Islam and work on the rest step by step. As for your friends and family, I know all about that and I come from a very prejudice community but I couldn't let it stop me. I kept a secret for a little while until one day I made it public online on one of their forums and I was met with the worse hostility and foul language ever experienced but it didn't stop me. I remembered that God is my Creator and he also created everyone and everything else. Who should I fear, my parents or God who created me and them? The answer is simple and it is a small price to pay compared to having truth, being on the right way and enjoying the good of the hereafter.
This life is short and has good and bad but the hereafter is not so. If you embrace Islam and start practicing it, others will see the good in you and perhaps they'll find the truth in Islam too, inshaAllah(God willing). I hope all works out and may Allah wa Ta'ala make your journey easy for you ameen.
to TTI community and you must be lucky that Allah has guided yu to the right path, which is islam. whom Allah guides him to the right path no one can make him deviates ..