First, contrary to your logic, scriptures say that there have been an infinite number of creation prior to this cycle (kalpa), and there will be an infinite number after the present cycle. See Brahma Sutras. This has been answered already in prior questions on this site. The inability to conceive of an infinite past is due to the observer being within the realm of Maya. Your question is dealt with extensively throughout many of the shastras. Maya produces the illusion consisting of time, space, and causation (desa, kala, nimitta). That which is beyond time is (Nirguna) Brahman. The Taittiriya Upanishad II.i.1 says (Swami Gambhirananda translator):
...Here is a verse uttering that very fact: "Brahman is truth, knowledge, and infinite...
[and from Sankaracharya's commentary on this verse] ...The text proceeds to show how It can be truth, knowledge, and infinite. As to that, there are three kinds of infinitude--from the standpoint of space, time, and objects. To illustrate: The sky is unlimited from the point of view of space, for it is not limited in space. But the sky is not infinite as regards time or as regards (other) substances. Why? Since it is a product. Brahman is thus not limited in time like the sky, since it is not a product. A created thing is circumscribed by time, but Brahman is not created. Hence It is infinite from the point of view of time as well. Similarly, too, from the point of view of substances. How, again, is established Its infinitude from the point of view of substances? Since It is identical with all substances. A thing that is different acts as a limitation to another. For when the intellect gets occupied with something, it becomes detached from something else. That, because of which an idea becomes circumscribed, acts as a limit to that idea. To illustrate: The idea of cowhood is repelled by the idea of horsehood; hence horsehood debars cowhood, and the idea (of cowhood) becomes delimited indeed. That limitation is seen in the case of distinct substances. Brahman is not differentiated in this way. Hence It has infinitude even from the standpoint of substances. How, again, is Brahman non-different from everything? The answer is: Because It is the cause of everything. Brahman is the cause of all things--time, space, etc.
Objection: From the standpoint of substances, Brahman is limited by Its own effects.
Answer: No, since the things that are the effects are unreal. For apart from the cause, there is really no such thing as effect by which the idea of the cause can become delimited. This fact is borne out be another Vedic text which says that "All modifications exist in name only, being supported by mere words; the earth alone is true" (Chandogya Upanishad VI.1.4); similarly, existence (i.e. Brahman that permeates everything) alone is true (Chandogya Upansihad VI.ii.1). Brahman, then is spatially infinite, being the cause of space, etc. For space is known to be spatially infinite; and Brahman is the cause of that space. hence it is proved that the Self is spatially infinite; for no all-pervading thing is seen in this world originate from anything that is not so. Hence the spatial infinitude of Brahman is absolute. Similarly, temporally, too, Brahman's infinitude is absolute, since Brahman is not a product. And becuase there is nothing different from Brahman, It is infinite substantially as well. Hence Its reality is absolute.
And in the Sarvasara Upanishad of Krshna-Yajurveda (verse 10) in Thirty Minor Upanishads, K. Narayanasvami Aiyar translator):
What is Brahman?
Brahman is that which is free from all vehicles, which is the Absolute Consciousness devoid of particularities, which is Sat (Beness) which is without a second, which is bliss and which is Maya-less. It is different from characteristics of that expressed by the word "Twam" (Thou) subject to Upadhis (vehicles) [qualities], or the characteristics of 'That' expressed by the word "Tat" subject to Upadhis. It is itself differenceless and is seen as the Seat of everything. It is pure, the noumenal, the true and the indestructible...It is that which is not continues to exist during the three periods of time. It is that which is. It is one without a second...It is that which does not perish even though space, time, matter, cause, etc. perish.
From causation comes space (akasha). From akasha, time. For further reading, Brahma Sutras (available here - https://www.wisdomlib.org/hinduism/book/brahma-sutras), Gaudapada's Karika (especially Chapter II) of the Mandukya Upanishad (available here - https://www.wisdomlib.org/hinduism/book/mandukya-upanishad-karika-bhashya), Pancadasi of Sri Vidyaranya Swami (translation by Swami Swahananda). You might also like Quantum Physics and Ultimate Reality: Mystical Writings of Great Physicists, Michael Green editor.
