The Gemara in Rosh Hashanah (11a) says that all what was formed during the Creation, was formed in their fullest stature (as linked in my comment). The Tosfos however, provides a fascinating piece of information, that I connected to this.
Tosfos (ד"ה לקומתן לדעתם לצביונם) explains that just as animals, beasts and birds grow physically, so in their height and length, they also grow in their wisdom, beauty and strength. Wisdom in this case, is knowledge. So, G-d formed man in his fullest stature, because then, he would have more knowledge than when G-d formed him like an infant. The Midrash Rabbah on Koheles conveys a similair idea, namely that Adam was full of wisdom (most meforshim explain that due to this wisdom, he was able to name all the animals).
The Torah says that G-d blowed "into his nostrils the breath of life" (Bereishis 2:7). The Alter Rebbe in Tanya says that this breath is the source of wisdom and intellect in the soul of Adam.
You ask, "why did Hashem wanted the humans wise from start". In Iyov (32:8), it says that understanding comes from G-ds breath. Rashi understands this to mean that no matter how old we are, it is G-d who gives us His wisdom.
not through days or old age, but it is the spirit of the Omnipresent.
The Torah in Bereishis 2:15 says that G-d put the man in the Garden, to work and to preserve it.
The Or HaChaim explains that this work was specifically Torah study.
The specific work required in גן עדן consists of Torah study.
So, might this be why G-d put wisdom in Adam on the first day of his creation?