Will this work? Should i give the gift i bought? Is there too much of an age gap?

Im 29, 30 soon and i have a huge crush on one of my friends little sister. The thing is she is only 21, is that too much of a difference? I have noticed her maturing into a young woman the last few years, she is so beautiful and we always have a chat and a laugh when im over there, i dont think my mate likes it. I told him ages ago i fancy her and he didnt mind! The thing is she has always had a boyfriend but she split with the last one 3 months ago and told me last week that she's bored of being single now n wants a man! She also said she likes older guys than her, she said atleast 5 yrs! She 'joked' what am i getting her for christmas? Ive bought her perfume she mentioned she likes n am thinking of putting my mobile number on the xmas card to her asking her does she fancy coming out for a drink with me to search for mistletoe?! What do you think, i adore her! Im not taking advantage am i? I split wiv my ex 6months ago! Women my age are so serious!