Question about health and body fat

Hello everyone, I've recently discovered about this forum and decided to give it a go. Anyways, I'm 19 years old and have CF. I've started going to the gym regulary (5-6 days a week) the past few months with the goal to acheive low body fat and build some muscles. Now, I'm at around 12% body fat and would like to go down to around 8% body fat to have more defined muscles. My parents are being parents and are worried about health issues. Question is, does having such low body fat can damage somehow my lung function or overall health? Thanks.
Source: Cystic Fibrosis Exercise and Fitness Forum - Category: Respiratory Medicine Authors: Tags: Exercise & Fitness Source Type: forums