i understand hw u feel because i ave being in that situation before.my cousin girl this time was in luv with me and wanted to marry me,she approached me,told me if i has was afraid of we getting along she would tell my mom.she was older.anyway though i was young then i had to find a solution.wat did i do?i did wat was best for us.u know wat,i believe in u that u can solve ur sister's problem.so get on to it u know the situation better,trust in u self and the solution will pop out.wish u the best.GOD HIS WITH U.AMEN

congrats just takia u are blessed