As you both are of major age then you can certainly get married as per the provisions of Special Marriage Act. No need to worry at all. No need to go to the court, Collect the papers related to your age proof and residential proof original copies of both of you and submit the application at the office of the Marriage registrar in your area. You will be given a date on which you can remain present before the registrar and get married.
Secondly, if you really feel that your in laws might create some issue out of it or they might bother you, then just go to the nearest police station and give an application to get protection. And remember, Police wont bother or harress you, just you being muslim or any minority religion. This is India, You can raise voice against anything happening illegal against you. Even you can take action against the Police if they bother you without any reason. But believe me Police doesn't do this kind of things.. they have hell lot of other work to do. I think you are thinking so much and getting dipressed without any reason. You are planning to get married.. this is not just an agreement but it follows with so many responsiblities in life. Once you get married, you will feel that the things you were facing and getting worried for before marriage are really petty problems than tolerating your wife every day.
Jokes apart.. but do not think much.. If you are of Major age and want to get married.. then just fulfill the Legal formalities and get married.
Adv. Yogen Kakade