When i run the "airmon-ng start wlan0" command these are the results i get

PHY Interface Driver Chipset

phy0 wlan0 wl Broadcom Corporation BCM43142 802.11b/g/n (rev 01)

(experimental wl monitor mode vif enabled for [phy0]wlan0 on [phy0]prism0)

Why does it say "experimental wl monitor mode" is this an issue because i have been trying to crack a WPA password and had no success even after leaving my command running for 24hrs.