No matter the size of your company; how many employees you have, customers you serve, or what your annual turnover is, the GDPR applies to you.
That magic 250 employee threshold is only mentioned once in the regulation and that’s in relation to record keeping. The GDPR requires that you keep detailed records of all processing activities – including records of consent, decision making, privacy notices etc. – but with fewer than 250 employees, you don’t need to. However, the rest of the GDPR still applies in full.