Might be a piece of cake, Most probably this timeline of 12 is based on assumption,
might take even less based on your requirements
have experience in Android app development for the past 4 yrs,
and published more than 20 apps in play-store,
Have worked on Taxi booking, Bus Booking, Food Delivery, Parcel Delivery apps etc..,
And also have hands on Prototyping with Figma, Adobe XD, Sketch,
Payment Gateways - Stripe, Braintree, Paypal,
Ads - ApoDeal, Adsense, Amazon etc.
feel Free to contact