Whilst I support anyone who joins this initiative I must warn you that such large dietary changes are difficult to sustain. Several newspapers have declared 2019 the year of the vegan, and so inevitably more people will join veganuary.com. Sadly many will fail, giving veganism a bad name.
As regular readers of my posts may see I try to direct people towards the healthy end of veganism, that of a whole food plant based diet without oils. This lifestyle is relevant on this forum because generally people here already have health issues, so the last thing I want to advocate is something that will set someone up for failure. Further I think that anyone with existing health issues is more likely to struggle with large dietary changes.
Instead swapping one food choice for another over time I think is more sustainable and is less likely to lead to complications. For example if you have eaten a lot of meat on a daily basis then you may have an oxalate issue. If that is the case then the last thing you should do is eat a lot of spinach each day because they are high in oxalates. Yes, you might be able to eat some but some gut issues can take several months to sort out, if not longer. Veganuary.com is only one month long, and so I think it is best for relatively healthy people.
Ps if you are keen on such an initiative then challenge22 may be better because they will assess you first and support you with appropriate dietary advice. But in the end unless you have hit a brick wall slow changes are best.