Repentance* cannot be delayed.
This is the flip-side of the better known (and also true) fact that anybody can repent at any time - up until the final decision to accept or reject Jesus's offer of resurrection into Everlasting Heavenly life.
The only time we can repent is Now. This follows from the above.
To say "I will repent", meaning at some time in the future I Could repent; is actually to reject God here-and-now.
To say "I will" is Not to repent...
Not to repent is to reject God, and to reject God has consequences; because immediately we will start to move-away-from God; to move towards the powers that reject, subvert, and invert God, the Good and Creation.
Anybody can repent that wants to repent. It is the wanting to repent that is the limitation. Anyone who says that "I will repent later" means "I do not want to repent". Not wanting to repent is not wanting to repent.
The immediate danger is that deciding "I do not want to repent, yet" makes it ever less-and-less likely that we will ever want to repent. (We see this all around us, in our own experience).
This is why we should repent Now - because Now is the only actual repentance.
(It is also why swift repentance (after sin) is so much better than delayed repentance; because repentance-delayed is to enter the never-never land of un-repentance. Which is (self-chosen) hell.)
*Repentance is the turning toward God, away from "sin". Sin is primarily about the rejection of everlasting, Heavenly, resurrected life. It is about choosing death. What we terms 'sins' are behaviours that are correlated-with those motivations which lead us towards rejecting Life, choosing death. Not to repent is to choose actually to be motivated - here-and-now - against God, Good and Creation. That is its danger.