The wedding itself is all about the bride and the dress. Just like Prom, its all about the dress

It doesnt matter who is there, what matters is will she b happy with whatever you do for a ceremony. And the bet way to find that out is ASK!
As for should you? All I can say is dont get married for ANY reason except that you love this person more than anything in the world and see her as your partner forever. You can be with someone and "love" them but to me, you need to be "IN Love" With them. The first one just means you like them and care about them as a person. 2nd means your feeling for them is over the top and cant see being with anyone else. As you grow older things change and you have to be willing to change with it.
Whether you marry or not but are together always make a point to be intimate with her regularly and I'm not talking sex

The best thing I did for my best relationship was at least once a day at some point in the day/night stop hold each other close be affectionate and kiss for at least a minute and just have a connection for a moment. Life gets busy and people get complacent and stop being intimate with each other and thats the start down the road of the end. My girl just LOVED that and when we first started doing it I sort of had to make/convince her to just stop for a minute

Now she's after me wanting her minute because she realized how much of a difference just that one thing made in our relationship

Its really important to stay connected with your partner, especially on an intimacy level. That can kill a good relationship in a heart beat.