Since you are not using the Play Store, you must enable installation from third-party sources.
Si aun así la experiencia es mala, tienes opciones más ligeras y 100% compatibles con Android 4.4.2: Descargar Facebook Apk Para Android 4-4-2
If possible, consider using (like Chrome for Android 4.4.2 – last version 70.0.3538.110). It’s often faster and more secure than an old, unsupported APK. Since you are not using the Play Store,