Spiritual Driving Licence
Bar Mitzvah compared to the age of getting a driving license.
According to Rabbi Aaron Hacohen, the first obligation of mitzvah after receiving bar mitzvah is the mitzvah of simchah. This comes still on the night of bar mitzvah itself, prior to the obligating of donning tefillin or being called for Torah reading.
Evidence of this fact be be found in Zohar, who writes: “R. Shimon Bar Yochai invited the leading scholars of the Mishnah to partake of a great festive meal which he had arranged... He was very happy... because (as he explained), “On this day, a holy and exalted soul descended... into my son R. Elazar, and on this joyous occasion, I shall experience supreme joy.”
Zohar Chadosh, Bereishis 15:4.
In addition, the Hebrew word for the “age of mitzvos” is called “gil mitzvos” and the word “gil” is associated with the word “gilah” meaning rejoicing and happiness. In a way, this is almost a literal meaning of the celebration.
Indeed there are many levels of the simchah — one for the person himself, that he has reached the age of obligation of mitzvos. There is also family simchah — having the merit of reaching Yiddishe Nachas for their family member. And above all, there is simchah of Hashem.
But there is also deeper level of Bar Mitzvah age, as the life of a person is now entering the state of personal obligations and maturity. In a way, this can be compared to be granted permission to drive in a secular world. On one hand, it increases the freedom of movement, on the other hand - greatly increases the chance of getting harmed in an accident.
With Bar Mitzvah, the person is entering stage of being exposed to Yezter Hara, i.e. his priveliledges come with responsibilities to overcome inner struggles and temptations. Commenting on Ecclesiastes, Rashi lays down the overall process that someone to come to the age of Bar Mitzvah experience:

טוֹב יֶלֶד מִסְכֵּן וְחָכָם מִמֶּלֶךְ זָקֵן וּכְסִיל. טוֹב יֶלֶד מִסְכֵּן וְחָכָם, זֶה יֵצֶר טוֹב, וְלָמָּה נִקְרָא שְׁמוֹ יֶלֶד, כִּי אֵין מִזְדַּוֵּג לָאָדָם אֶלָּא מִבֶּן שְׁלשׁ עֶשְׂרֵה שָׁנָה וּלְמַעְלָה, וְלָמָּה נִקְרָא שְׁמוֹ מִסְכֵּן, שֶׁאֵין הַכֹּל שׁוֹמְעִין לוֹ. וְלָמָּה נִקְרָא שְׁמוֹ חָכָם, שֶׁהוּא מְלַמֵּד אֶת הַבְּרִיּוֹת לְדֶרֶךְ יְשָׁרָה. מִמֶּלֶךְ זָקֵן וּכְסִיל, זֶה יֵצֶר הָרָע, וְלָמָּה קוֹרֵא אוֹתוֹ מֶלֶךְ, שֶׁהַכֹּל שׁוֹמְעִין לוֹ, וְלָמָּה קוֹרֵא אוֹתוֹ זָקֵן, שֶׁהוּא מִזְדַּוֵּג לוֹ מִיַּלְדוּתוֹ וְעַד זִקְנָתוֹ. וְלָמָּה קוֹרֵא אוֹתוֹ כְּסִיל, שֶׁהוּא מְלַמֵּד לְאָדָם לְדֶרֶךְ רָעָה. אֲשֶׁר לֹא יָדַע לְהִזָּהֵר עוֹד, שֶׁאֵינוֹ יוֹדֵעַ כַּמָּה צַעַר וְכַמָּה יִסּוּרִין בָּאִין עָלָיו וְהוּא אֵינוֹ נִזְהָר מֵהֶם.

“Better is a poor and wise child than an old and foolish king who no longer knows to receive admonition” (Ecclesiastes 4:13).
“Better is a poor and wise child than an old and foolish king.” “Better is a poor and wise child” – this is the good inclination. Why is it called a child? Because it only associates with a person from the age of thirteen onward. Why is it called poor? It is because not everyone heeds it. Why is it called wise? It is because it guides people to the straight path. “Than an old and foolish king” – this is the evil inclination. Why is it called “king”? It is because everyone heeds it. Why is it called “old”? It is because it associates with him from his youth through his old age. Why is it called a “fool”? It is because it guides a person to an evil path. “Who no longer knows to receive admonition” – he does not know how much pain and how much suffering will afflict him, but he is not cautious in their regard.

Rashi's description comes with painstaking similarity with the freedom of the movement for any motorist. The idea of ultimate joy is shadowed with the responsibilities that one need to incorporate in full diligence of every turn. Driving in fulling confidence leads to suffering. Only following dedicated signs on the road can lead to avoiding accidents. Hence, the joy of driving is only achievable through a full compliance with external guidance. In comparison to this analogy, spiritual freedom can be only achieved through a full compliance of studying and following the path of diligence in mitzvos.
Or as Mishna Avos powerfully states: “There is no free man except for one who engages in the study of Torah.”