Nice idea to do a gift of crypto to a love one. Reading through your story I was thinking the person you wanted to gift to does not understand crypto because the person may not value it but the very good news is that she understands and already into cryptocurrency. That is nice and congrats to your sister, wishing her more joy and happiness plus more hodling for greater profit in the future.
She already knows that I am into cryptocurrency for a long while,
However, I was thinking you will gift her at least 5 Ethereum
because you said you have been into crypto for long and that means you could own maybe part of bitcoin , altccoins especially erc20 tokens.