I am rather confused about your verb tenses: "tears ran out" of your eyes, but "this is the third time" your aunt had cancer. Are you describing an event in the past, or are you placing yourself inside the experience? Please clarify this for consistency. The general timeline of your description could also be clarified- is this something that has taken place recently? How recently? You describe your aunt in the present tense ("she is"), and yet you say the experience "affected" your life in the past tense.
"She is always happy and upbeat when I see her, she has been very strong and not letting this get her down."
First of all, the first and second parts of this sentence are both independent clauses, meaning they need to be joined with a conjuction ("[...] when I see her, and she [...]"). Also, the second part of your sentence needs to be changed to "she has been very strong and has not let the experience get her down", in order to maintain parallel verb structures.
"She still sees this just as something that god has put in front of her to let her surpass and continue with her journey."
In this context, "god" should be capitalized. Your use of the word "surpass" is also rather dubious. I would change it to "overcome", as in a challenge to be overcome.
"Remember that the journey ahead is a long one, but one that shouldn't be taken lightly and that you will surpass and look back as just a tiny bump."
This sentence does not make very much sense to me in the way it is structured. I think I know what you are trying to say, but perhaps try rephrasing. Something like "Although the journey ahead is long, I know that when I look back the challenges I have surpassed will only seem like a small bump in the road" would be clearer.
Overall, I feel like your story is engaging and clearly inspirational. However, I feel like you need to rework some sentences for grammar and clarity, and you could also think of adding more specific examples- everything right now is mostly abstract.
Rebecca L.