I wonder if you asking is your answer?
Take time to think about if you really want it.
If so, I suggest to make it something more symbolic of your child, like a favorite plush toy. The drawing is sweet, and I agree with another poster to frame it.
The foot is generally a bad place for a tattoo when it comes to pain, and more importantly, longevity (fades quicker - there are videos and articles/blog posts on body parts and tattoo longevity).
If you decide to go ahead with it, really think of what you want, in what style. Then research what artist will be the best for the style you want, look at cleanliness and knowledge of proper procedures, and also reviews of the attitude of the artist. They should have plenty of pictures of their work on social media. You can then talk to the artist and see if he or she wants to do it, and then have them draw up your ideal tattoo.
I know single needle tattoos are trendy now, but I would advise against that for the sake of preventing blow out and quick fading.
As for the aging thing, that’s something for some to consider of course. Part of that is genetics, and part is good care of your body and tattoo. Look up tattoo aftercare as well, also lots of good info out there to maintain vibrancy and avoid it turning into a blob eventually (sun damage).