How do you know for sure that you'll even have sex on the wedding night? Desi weddings run really late at night and are very exhausting. It doesn't necessarily have to take place on that night. It could take place later as well. I don't agree with your mom's approach or advice. First of all, she put all the responsibility of pleasuring on one person and secondly she didn't take into account that "wedding night" experiences vary. Communication (most importantly with your husband to be) is key here. When the time comes (be it on the wedding night, or the day after, or the honeymoon), talk to him about it. Communicate your fears, what feels right, what doesn't etc. because he can't read your mind and I doubt that he'd want you to feel uncomfortable. It can't be much fun for him if you're not into it. I think that sex is more emotional for women than it is for men. Therefore, if you don't communicate with your husband, it has the potential to have uncomfortable emotional consequences as well. It involves two people, so approach it in a cooperative/mutual way as opposed to the "martyr"-like notion that your mom has given you.
sister, you're getting into a marriage. it's like rowing a boat - both parties have to put in their efforts to please EACHOTHER. It's not that only you have to please him - it's supposed to be two way. forget everything, just be normal and main thing of all, pray 2 rakaat's nafl and ask for Allah's help. There's nothing to be ashamed about. Allah has said in Sura Yaa-Siiin ayat 36, "Glory be to Him Who created all the sexual pairs, of that which the earth groweth, and of themselves, and of that which they know not!"
Look at this world - how many married couples do you see? have they not experienced their first night? so if millions have done it without problem, why should you be an exception? Remember, if you're conscious about something, you won't be natural and the fun is gone. this night is not about him but about "both of you". It's not about perfection, but about love and it is those little imperfections that make a journey of life together. so just forget the stress and live it as it should be lived. I know asian ammi's can make simple things difficult and make us lose the fun out of things just because they're obsessed with daughter's marriages going perfect and yet it is the want of this perfection that makes things into a machine instead of life.
So sister, don't worry. Inshallah everything will go perfectly and may the two of you always love eachother and be happy. Inshallah I'll also pray for you and if possible you also pray for me because I have loved a girl for the past 17yrs but unfortunately she's not interested in me and I would never want to force her into marriage (she's my cousin). I love her too too too much to ever get married to anyone else. I'm just hoping that Allah would create love in her heart for me (her name is Jameelah Zahra).
So my sister in Islam, may Allah help you and guide you. My duas are with you.