Awakening of Kundalini is possible without mentor/guru?
Yes, Kundalini can be aroused without the help of Guru also.
Complete Works of Swami Vivekananda / Volume 1 / Raja Yoga / Chapter IV / The Psychic Prana:
The rousing of the Kundalini is the one and only way to attaining Divine Wisdom, superconscious perception, realisation of the spirit. The rousing may come in various ways, through love for God, through the mercy of perfected sages, or through the power of the analytic will of the philosopher.
Swami Vivekananda has covered the topic of Kundalini in great detail which you can find in the above link.
Note: “The question: Awakening of Kundalini is possible without mentor/guru?” is licensed by Stack Exchange Inc (https://hinduism.stackexchange.com/); user contributions licensed under CC BY-SA.