Ecstacy is fairly safe. The only negative is the possible long term effects of depleted serotonin etc. I would research into it and see if you accept the risks. If you do do it and you only do it once I would do it at a rave where loads of people are doing it. It is fun to do it at home witha few mates but for the full experience do it a rave. The first time I did it at one it totally blew my mind and I had one of the best nights of my life. You sound pretty sensible only doing a half I've always done whole pills but do what ever you feel comfortable with. Don't do more than one at a time unless you have done the pills before and know there strength.