Asalaamu Alaykum,
First of all congratulations on your reversion, and May Allah bless you and your husband to be. Indeed, the marriage is a beautiful covenant between 2 persons (in this day and age i have to emphasise between a man and a woman), a pledge to go through life supporting one another, being loyal to one another, upon what? Upon obedience to the One who brought the 2 together, being garments for one another, and comforters.
Since marriage is instituted by Allah, it is appropriate that it is seen as an act of worship, as a means of drawing closer to Allah. How would it be then that this pledge of purity, is tainted with haraam? One of the ways that we deprive ourselves of the blessings of Allah, is by disobeying Him and giving preference to the obdedience of others. How so? Of course my sister, you do not want to be seen as 'imposing' things upon your family, but would you rather please Allah, who is the only one that possesses reward, or the people no matter how close they are to you through blood-ties, who possess not the least ability to reward or punish you? Of course you want your marriage to be blessed, but by whom? Allah the Most High or the people?
We believe that Alcohol is forbidden by Allah, and for a good reason. When we are teaching our children who may not understand the dangers of something, do we not impose limits upon them, for their betterment? Same way, by not allowing alcohol in your wedding, you are actaully benefitting your guests, as Islam is not only centred on the slef, rather it is to be used for the benefit of others. The legality of alcohol should not be considered in light of the probability of someone getting drunk, rather one sip of that haraam stuff is sufficient to show the intoxication of ones mind and obliviousness to the Laws of Allah. Feel confident, Allah is on your side! This will be a way of doing dawah to your family and friends, and subhanAllah, imagine your reward; on your wedding day you have encouraged good and forbidden evil! As with all things, calmly explain things to others with wisdom, and don't centre it on alcohol, start from your beautiful relationship with Allah, and how He in His infinite Wisdom has commanded us to refrain from some things, and attain to others.
May Allah bless you, and forgive me if i have said anything wrong.
Wassalaam