If the 6 days of creation were 6 x 24 hours then the world is young. It's billions of years old. Geology is plain. If you think that the world is only a few thousand of years old you are wrong. Every sedimentary rock tells it's story that it's many millions or billions of years old.
If you want to try to say that Genesis is talking of periods of time in which a day may be many billions of years then the flowering plants need to have insects and other animals to fertilise them. You cannot have it both ways.
Nope. The Hebrew word for day ("yom") can mean extended ages of time.
Strong’s 3117 – yowm (yom)
d. days, lifetime (pl.)
e. time, period (general)
Yowm - Old Testament Hebrew Lexicon - New American Standard
In my personal Strong’s Concordance, on page 48 of the definitions, it also has “or fig. (figuratively) a space of time defined by an associated term” (and context).
You apparently didn't study the context of creation events either.
For instance, on the third "day," God formed the land out of the seas. There is no time frame given for the formation of the land and seas. Some time after the land was formed, God created the plants:
Then God said, "Let the earth sprout vegetation, plants yielding seed, and fruit trees bearing fruit after their kind, with seed in them, on the earth"; and it was so. (Genesis 1:11)
And the earth brought forth vegetation, plants yielding seed after their kind, and trees bearing fruit, with seed in them, after their kind; and God saw that it was good. (Genesis 1:12)
The text clearly states that the earth "sprouted" the plants (the Hebrew word deshe, Strong's #H1877, usually refers to grasses). The Hebrew word dasha, (Strong's #H1876) indicates that the plants grew from either seeds or small seedlings in order to have "sprouted." In addition, these plants produced seeds. The Hebrew word here is zera (Strong's #H2233), which is most often translated "descendants." This makes matters very difficult for the 24-hour interpretation. Not only do the plants sprout and grow to maturity, but produce seed or descendants. There are no plants capable of doing this within a 24-hour period of time. Things actually get worse for this interpretation. Genesis 1:12 clearly states that God allowed the earth to bring forth trees that bore fruit. The process by which the earth brings forth trees to the point of bearing fruit takes several years, at minimum. God did not create the trees already bearing fruit. The text states clearly that He allowed the earth to accomplish the process of fruit bearing through natural means. Because the process of the third day requires a minimum period of time of more than 24 hours, the Genesis text for the third day clearly falsifies the interpretation that the days of Genesis one are 24-hour periods of time.
Genesis Clearly Teaches that the Days Were NOT 24 Hours
But it gets even worse for you in thinking the Bible stipulates 24 hour days.
Genesis 2:4 literally reads, "in the day (yom) of the Lord God making (made) the earth and heavens."
The author of Genesis, who also wrote of the 'days' of creation, describes those 'days' as one day, or one time period. It's the same Hebrew word. The implication is clear - Moses' “day” (yom) in Genesis 2:4 refers not to a 24-hour day but, rather, to a much longer period of time—in this case, the entire span of creation events.
And God doesn't need fertilizer to grow grass.