What are good places to travel in central America for a 21 year old. adventure stuff?

I'm a 21 year old female. I've allready done Cancun and want to go somewhere other than mexico. I'm not really looking for bars and stuff, more into adventure stuff and outings. Any suggestions people?

Costa Rica or Panama

I cant say much for other Central American Countries, but you should try Honduras. Check out the maya ruins and explore it's fauna and national parks.

Hike up to the Macchu Pichu in Peru, or travel to Argentina and explore the beautiful Andes and visit the busy and fun Buenos Aires

I traveled through Central America by bus when I was 21 (5 years ago). Here are some places I would recommend, based on what you say you're looking for:

- Antigua & Lake Atitlán in Guatemala (volcanos, beautiful scenery, enormous mountains, lakes, plenty of guided hikes/adventures)
- San Cristobal de las Casa in Mexico (just the trip to get there is amazing, but then there is so much stuff to do, culturally and also travel-wise. I went on a canyon river tour, rode a bike to a nearby indigenous village and saw awesome independent movies from all over the world)
- Grenada in Nicaragua (this place is a little off the beaten path, was kind of still undiscovered when I went there but had an awesome hostel for $6/night. an enormous lake, neat day trips, volcanoes, huge markets, very fun and beautiful colonial town!)
- West coast of Costa Rica, there are tons of beaches. The sky is really the limit there, and of course it is a wealthier country which brings benefits and drawbacks.

El Salvador =)