# Cool script. Not sure if you are still improving it but I see one thing right away that you could create a dl_video method to eliminate the duplicate download video code. E.g.:

def dl_video(link):
    download_video = link.streams().first()
    print('Download Started')
    download_video.download('videos/')

# And while you're at it, a dl_audio:

def dl_audio(link):
    download_mp3 = link.streams.filter(only_audio=True).first()
    print('Download Started')
    download_mp3.download('audio/')

# So it'll look like this:

...

while True:
    user = input('To Download Video/Audio Y/n: ')
    if user == 'Y':
        url = input('Enter Url: ')
        link = YouTube(url)
        form = input('Do you want to download video or audio: ')
        if form == 'video':
            dl_video(link)
        elif form == 'audio':
            warn = input('Audio Downloads take longer Do you want to Continue Y/n: ')
            if warn == 'Y':
                dl_audio(link)
            elif warn == 'n':
                vid = input('To Download Vid Y/n ')
            if vid == 'Y':
                dl_video(link)
            elif vid == 'n':
                exit()

...