Bluetooth headphones have a delay lag

I've recently switched to a pair of bluetooth headphones on my laptop But when i use them the sound is lagging by 3/10th of a second.

I used this video to check: https://www.youtube.com/watch?v=ucZl6vQ_8Uo

Is it normal for bluetooth headphones?

The sound is great, and as long its just streaming music its fine. but gaming or video watching causes out of lip sync issues.

I'm using a dell laptop inspirion 15 7000 series with Betron BN15 headset.

There will always be SOME delay, compared to wired headphones.
Bluetooth transmission is not instant, but the main issue is buffering. You need to hold a bit of the audio before you can compress and send it.

It is certainly possible to reduce it to make it unnoticeable, but you will be dependent on the hardware and software of the system you connect to, and the software playing the sound.
Often, a small buffer size (for low latency) may cause other problems.

Some recommend the APT-X codec , but that is often not up to you.

BT 4.0 and higher will usually have much lower latency, as long as your computer also supports it.

Official headsets for Playstation (3?) consoles supposedly have no noticeable lag in most games , but act differently with other devices.

So what can you do?
There's no universal solution for games, but for video, most players (smplayer, vlc...) will have the option to alter the audio/video sync. Set the audio to play at -0.3s with respect to video.