Yea, people are undercutting. It is a competition. So.. you go AH and undercut the previous dude. Be decent and undercut by 1 silver, don't be "that" guy.
You will sell it, 100%. I never met a guy why has 5000 Berserker enchants and he can't sell them. If you are reeeealy worried about that, make, lets say, 10 enchants. Sold all, good make next batch. Sold only 7? Make another 3 and dump it in. Tough, remember, you could probably sell 11 or more, you just lost gold. If you want everything right tomorrow by noon... it doesn't work like that. Think in, minimum, weeks. Months.
It is 5% tax, you are thinking about Neutral AH.
Edit: basic human trait - if you do something, you will become good at it. Just go and start.