QUOTE: The age of my 20’s was a rollercoaster ride I will never forget.

first, most numbers should be spelled out... next, 'the age of my
20s' is awkward... 'My twenties were a rollercoaster ride...' reads better and makes better sense... less is almost always more...

QUOTE: I ventured out on my own, cramped in a dinghy cardboard box apartment at 19 years old and explored life to the fullest.

a run-on sentence with several goofs:

'ventured out/cramped in' seems to contradict itself, as well as not make much sense...

a 'dinghy' is a rowboat, so you must mean 'dingy' which means not clean...

'at 19 years old' should begin the sentence and not be dumped into the middle to muddle the meaning...

the age should be spelled out, 'years old' is extraneous...

and some of the wording is off grammatically or common expression-wise...

one better way to say the same thing would be:

At nineteen, I ventured out on my own to live in a cramped, dingy, cardboard box of an apartment--planning to explore life to its fullest.

QUOTE: By the time I was 29 years old, the prosaic dating scene had grown stale and I wanted to settle down, even though I’d never considered myself the marriage type.

...some minor goofs that can be easily corrected... one way:

By twenty-nine, the prosaic dating scene had grown stale and I wanted to settle down, even though I’d never considered myself the marrying type.

i don't do major nit-picking in posts, but if you want some help fixing and polishing this, i'll be happy to do it by email...

love and hugs, maia
maia3maia@hotmail.com

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www.saysmom.com

"You must BE the change you wish to see in the world." Gandhi