B1 is AP level, which means advanced/independent user; it takes roughly 5 years with about 4hours of instruction a week + daily hw.
It typically takes a minimum of 1 year of continuous study to reach A1 (basic) but you can probably speed that up by dedicating several hours to it every day. A1 is the easiest level to reach and if you do it full time you can probably reach it within 3-4 months. A1+ is a good goal, A2 would mean great aptitude (it takes 2-4 years to “typically” reach that level).
Note that the Defense program is meant for people who have been selected for their high aptitude for language learning and do it as their full time job in an environment designed to optimize that learning. The learning scale was adapted for HS and college learners because so few students reached even “Level 1” on that scale and it was intensely discouraging to them because it felt “low” (when in fact it wasn’t.)
First step would be to get the absolute basics - self-introduction, to be to have to go and a handful others in the present tense affirmative/negative/interrogative forms. See if you can find a book called English grammar for students of Italian and any basic grammar/workbook. Give yourself two months. Add Duolingo as you go - it teaches some automatisms through repetition. Reading novels that take place in Italy can also provide essential background information and little bits of vocabulary: Camilieri, Donna Leon, Elena Ferrante, etc.
After a couple months,
if you have Netflix look for Italian-language films and series, like Il treno dei bambini , C’e Ancora Domani, La Meglio Gioventù, My brilliant friend..
which show life in Italy as it used to be and how it’s become what it is, the background everyone has in the back of their mind because it really wasn’t so long ago. It’ll help you hear Italian and then you can select 1-2mn bits you’ve watched with English subtitles and you can switch to Italian subtitles: do you catch the words? For A1-A2 levels a minimum of listening three times to the 1-2mn bit is usually required. But the more you work on that the more you’ll catch. Then when you catch everything important after 3 viewings, you can increase the length of video or decrease the number of viewings.
That + workbook+ programs suggested upthread are likely to keep you busy through Summer 2026.
Adding personal lessons, especially the first month and then at regular intervals as check ups, is a great motivation. If there’s a local college (or a community education center) you can see if there are Italian courses there and (beside enrolling) you could see if a lecturer or advanced student would be willing to tutor you. And if you’re able to, you can join a family language camp at Concordia Language Villages, to see if you can function in every day situations entirely in Italian. 