discrepancy in wifi speed and internet speed.

Hi,

I am not so well-versed in wireless, so bear with me.
I have a 60 megabit internet connection , which I have shared via wifi using a Raspberry pi 3 model B.

The problem is, I do not get the full strength of the internet connection on wifi.

$ speedtest-cli
on the router reports correct and perfect connection speed, which clearly indicates it gets the required bandwidth.

However on a wifi client, even if I am the only one connected , the wifi network connectivity speed is reported to be fluctuating but never as fast as the pppoe connection.

speedtest-cli from my wifi client (a 150mbps usb wifi adapter) , NEVER shows 60 mbps , it gets around 30 , 35 at the maximum.

Is this normal or am I going wrong somewhere ?

Below is the hostapd config :

interface=wlan0
ssid=someid
driver=nl80211
hw_mode=g
channel=11
ieee80211n=1
wmm_enabled=1
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_passphrase=dummypasswd
rsn_pairwise=CCMP

thanks.