I am 21F and just like in your case, I started Stuttering when I was 18 years old. I don't really know what caused it. .and as you said you've been hiding it ..I too had been hiding it but earlier this year it got exposed to all my juniors, classmates and seniors. I told my family about it and it's impact on my life with tears in my eyes...I can totally understand what you must be going through..its very difficult to open up about it even to the people who are very close to us ..I suggest you to take speech therapy...and wish you a happy married life ..and although its extremely difficult to open up about the stutter, try not to hide it as it will only worsen it. Gather some courage and tell about it to your family members and invited people before the marriage ceremony. This might also help you. Although it's quite strange to begin stuttering at adulthood, never think that you are alone.. coz same thing happened with me. Thank you for posting this... and have a happy married life. May your upcoming days be full of love, understanding and respect 🙂