It possible to start showing signs of cystic fibrosis in my teens?

Yes. Milder forms of cystic fibrosis are often diagnosed in teens or young adults. If you have typical symptoms of cystic fibrosis you should talk to your physician about having a sweat test.
Yes. CF can even be diagnosed much later in life. If you are concerned, then a sweat test should be ordered.

Related Questions

My 2 year old son had a throat culture that came back with a high reading of pseudomonas, is this a sign of cystic fibrosis?

Need to rule CF out. I would have the culture repeated. Unfortunately, studies have shown 49% of 2 year olds had positive throat cultures for pseudomonas aeruginosa. Sweat testing and genetic testing should be performed. Check to see if newborn blood screen tested for cystic fibrosis (cf). Read more...
CF screening. Pseudomonas aeruginosa is one of the common bacteria involved in CF sinus and lung disease. It is found in some patients who have mechanical ventilation or in cases of exposure to contaminated water as well. You should inquire about a CF sweat test at your doctor's office to screen him for cf. Prmg respiratory pediatrics can review his records including growth chart (fax 858 259 9689). Read more...