here

"why am I here?" good question. but, before one can tackle this question, there's another, even more basic, question: "where's here?"

"here" is the universe--HUGE, complex and VERY, VERY old. here's what we know:
The Universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy.Wikipedia

Mass (ordinary matter): At least 10 to the 53rd power kilograms
Age (within Lambda-CDM model): 13.799 ± 0.021 billion years
Main contents: Ordinary (baryonic) matter (4.9%); Dark matter (26.8%); Dark energy (68.3%)
Diameter: Unknown. Diameter of the observable universe: 8.8×1026 m (28.5 Gpc or 93 Gly)
Shape: Flat with only a 0.4% margin of error
Estimated size: The observable Universe is, of course, much larger. According to current thinking it is about 93 billion light years in diameter. 

WOW! 

• "Mass (ordinary matter): At least 10 to the 53rd power kilograms". 1 kilogram = 2.20462262185 pounds. that would be about 2,204,622,621,850,000,000,000,000,000,000,000,000,000,000,000,000,000,000 pounds. planet earth's mass (in kilograms) is 5.9736 times 10 to the 24th power. so, the universe's mass is about 167,400,000,000,000,000,000,000,000,000 times planet earth's mass. WOW!
• 13,799,000,000 years old. WOW!

I could go on... but, what's the point? the universe's size and age are immensely difficult--if not, impossible--to grasp. which leads us to the question: "where did the universe come from?" the short answer is that we don't know. 

a popular theory is the "BIG BANG". What Is the Big Bang Theory? | Space all of the matter and energy in the universe, contained in an incredibly small space, exploded 13,799,000,000 years ago into the expanding universe that we know today. WOW!

however the universe came to be, we know that it's magnificent--which leads us back to the question "why are we here?" 

all of us know that, in our world, something doesn't come from nothing. we know that, within the universe, it takes matter or energy to create matter or energy. the short answer to the question "why are we here?" is that we're here because we were born. for most of us, an egg from a woman was fertilized by a sperm from a man and, about 9 months later, we were born.

anthropologists say that between 5,000,000 and 7,000,000 years ago, apelike creatures in Africa began to walk on two legs. it's commonly believed that recorded history began about 5,000 years ago. for everything that happened before 5,000 years ago, we don't have a written record of what happened. needless to say, it's a LONG time between 5,000 years ago and 13,799,000,000 years ago! (it wasn't until the invention of the printing press, believed to be sometime in the 1440s--about 580 years ago--that written records began to proliferate.) 

some of the oldest written records are the dead sea scrolls--which contain most of the books of the Hebrew Bible. the dead sea scrolls date from 408 BC to 300 A.D.--the oldest being about 2,400 years old. the Hebrew Bible definitively states that God created the universe and God created us. 

does anyone have a better explanation?

https://commons.wikimedia.org/wiki/File:NASA-HS201427a-HubbleUltraDeepField2014-20140603.jpg

NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI) [Public domain]