The short answer is "Yes" - note the previous verses:
Deut 23:21-23 - If you make a vow to the LORD your God, do not be
slow to keep it, because He will surely require it of you, and you
will be guilty of sin. But if you refrain from making a vow, you
will not be guilty of sin. Be careful to follow through on what comes
from your lips, because you have freely vowed to the LORD your God
with your own mouth.
That is, one was free to either make a vow or not. However, if one makes a vow, then the law stated that the vow must be fulfilled expeditiously.
Note the Pulpit commentary:
Verses 21-23. - A vow to the Lord, once made, was to be religiously
kept; the Lord would require it, and to refuse or neglect to pay it
would be held a sin. No one, however, was under any obligation to vow
ie, that was to be a purely voluntary act. That which is gone out of thy lips thou shalt keep and perform... according as thou hast vowed
unto the Lord thy God of free-will (נְדָבָה, spontaneously). (For the
law concerning vows in general, see Leviticus 27, and Numbers 30.)