Let me give you a couple of quick pointers before I retire for the night ...
Through my life I had always had a love for science.
Use "throughout" instead of "through" here. "Throughout" denotes time while "through" is more associated with space/location.
I have always been particularly interested in the science of life, biology.
Try to punch up the verbs whenever you can with the active voice instead of the passive (any form of "to be"). Using the active voice also takes the words count down and allows you to put in more "meat" and less "cotton candy." The "biology" tacked onto the end of this sentence is awkward. Try something like this instead: The science of life, biology, particularly interests me.
I have been interested in everything from the smallest organism to complex creatures such as elephants to bizarre plants.
You used the word "interests" in the previous sentence. You can repeat words, but I feel like it is best to mix it up some. This sentence is another example of how you could take things into the active voice: Everything from the smallest organism to complex creatures such as elephants to bizarre plants captivates me.
Everything about life in general was fascinating.
Was? It isn't any more? The verb tenses are jumping around a bit in your piece. Try to smooth out the past/present/future/past/future/past/present issues as much as possible.
That's all I can do tonight! I start school in the morning.