Yes, if you can come up with any of the following
- deterministic finite automaton (DFA)
- nondeterministic finite automaton (NFA)
- regular expression (regexp of formal languages)
- regular grammar
for some language $L$, then $L$ is regular.
Just to complete the list: $L$ will be also regular if
- it is finite
- you can construct it by performing certain operations on regular languages, and those operations are closed for regular languages.
- using Myhill–Nerode theorem if the number of equivalence classes for $L$ is finite