geting my mom to let me stay with my boyfriend

i am almost 20 years old. me and my boyfriend have been together for about 2 1/2 years now and i am trying to get my mom to let me spend the night with him tomarrow. he is a drummer in a band and they are playing a show that is about 3 hours from here. we wont be geting home untill 2 or 3 am. and i dont like driving that late at night. but i have to go to help with set up and to spend some much needed time together. we wont be sleeping in the same room or anything like that. i just think it would be better for me and him and also my mom because she wont be up all night waiting on me to get home. but i cant seem to convience her. what would you do if you was me and if you have a daughter what would you do? plz let me know
thanks

Kendo welcome here to the forum
If I'd be your mum I'd let you spend the night with him. Why is she refusing?

she just says no. thats not way, even when i ask her why.

that's strange. she gives no reason for her refusal?

you are 20 yrs old hunny your life your discion just because you live with her doesn't mean she controls your love life. if i was you id stand up to her or your boyfriend might get tired of just a friendly date here and there. omg 2 and a half years and you havent spent the night with him ive been with my boyfriend 8 months today actually and i stay with him all the time. the greatest feeling ever is just being in his arms youll never feel that if you dont just stand up for yourself