See in general there are no problem. But if you are targetting UPSC CSE then the age limit if 21 to 32 years. So if you take even 2 years of gap then you have good amount of time available to be eligible for it. Apart from this you should keep in mind, that for civil services you need to have a UG degree. So if you take a gap then no problem but you must be serious about your preparation as you know UPSC CSE is the toughest examination. The eligibility criteria is also the same for the state PSC's as well.

To know more about UPSC visit the link below:

https://competition.careers360.com/articles/upsc-ias-eligibility-criteria

To know more about UPSC CSE preparation tips visit the link below:

https://competition.careers360.com/articles/how-prepare-for-upsc-ias

I hope this answer helps. All the very best for your future endeavors!