Would sound better as
“First, I am 25 years old and I have no previous experience with arranged marriage.
Problem 1 :
Avoid using adverbs to describe ordinal lists (firstly, secondly, thirdly, etc.) for the following reasons: 1) while secondly and thirdly sounds okay in English writing, firstly sounds stupid, and since more consistent writing is easier to read, you should decide to write the same each time; 2) since most people do not want to write or type two more letters. Writing is tiring enough. So you may as well only write first, second, third.
Problem 2 :Avoid contracting pronouns and verbs (e.g. changing “I am” to “I’m”) unless you are quoting people who are speaking.
Problem 3 :“With” sounds better than “on.” You cannot have an experience on something unless it is a physical. But you can have an experience with abstract things.
“People who was born in 80s maybe have more blind date as it becomes a more and more fashion social phenomenon, especially in China. “
Sounds better as
“People who were born in the 1980s had perhaps more blind dates, as these became a more fashionable social phenomenon.”
Problem 4: Verbs should match nouns. Since people is plural (many persons) you should use “were” rather than “was.”
Problem 5: 80s is a proper noun, so it should be preceded by “the”
Problem 6: “Date” should be plural, since more indicates something that is more than one.
Problem 7: “Fashion” is a noun, but an adjective should precede “social.” That adjective is fashionable.
“If you have been 24years or older, not having a blind date is unusual.”
Sounds better as
“If you are 24years or older, not having had a blind date is unusual.”
Problem 8: You are talking about either the present or the past, but verb tenses should match in the first and second parts of a “if…then” conditional sentence. The verb