Hi Cassie!
I would tell the truth about your age, especially if you look younger. I am 35 and could pass myself off as 29 or 30, but it's much nicer for people to be pleasantly surprised when they first see you! Bear in mind that a lot of ladies do lie about their age so to counter this, more experienced punters often automatically add a few years on just as a general assumption; I say I'm 35, so a lot of them assume I'm going to be 40 - it doesn't take a genius to realise that if they then arrive and find me to look about 30, then they are going to be happier than if I'd just lied and said I was 30 in the first place!
You can build your own website for free - there are template sites like Moonfruit, or if you're not that confident you can get a nice professional site for less than you probably think (I often get compliments on mine and it was not that expensive). I would definitely put up an Adultwork profile to be getting on with too - it doesn't cost anything and is an easy way to start yourself off (even if the site is not generally for the squeamish!) Good luck!