You need to learn / know lab safety to handle to handle to chemicals
and living samples. You'll have to do some self-directed reading and
learning on your own, but that does not mean people won't help you
along the way. Express your interest to you biology teacher, they may
be able to provide resources such as textbooks or access to the school
labs. Personally in a small rural public high school I had access to
undergraduate physic textbooks and was given access to the chemistry
lab on the weekend by my teachers who were supportive of my interests
and curiosity. If you live near a college or university, look at the
course calender, depending on the programs and resource they may allow
you enroll in a class as a non-degree / non-program student to take
1-2 courses. Don't forget to check spring/summer sessions, and summer
workshops / camps.
A 'step 0' project you can do today is "5 minute DNA extraction" which
uses household items to do a very simple project, to get your feet
wet:
<http://www.instructables.com/id/5_minute_DNA_Extraction_in_a_Shot_Glass/>
or <http://ohphook.notlong.com/>
In the diybio archives, there are references to educational material
available and/or being developed for high school students:
<http://groups.google.com/group/diybio/topics?gvc=2>
<http://groups.google.com/group/diybio/browse_thread/thread/1921da7d685845fa#>
Be safe, be curious, and enjoy,
Michael