I've known my husband since we were teenagers, and we got married when I was 23. I'm now almost 28, and we have an almost 2 year old daughter. Before we married we both dated other people and we kept coming back to each other. We just KNEW we were right.
We've had some major rough patches, some of it is from us being young, and others perhaps cultural differences that we're overcoming. I wouldn't change anything that I've picked, but it's worked for me.
Trust me, you'll KNOW when the right man comes along. Make your decision when you are ready, not when anyone says you "should" be ready.
And no matter what, there will be rough patches it's up to the love that you and your future spouse have to see them through.
Marriage is really hard work, it's 100% of yourself every day. Be happy as you are, and trust your instincts - when you're ready and the right man comes along everything will fall into place.