generally speaking, concerto is not for 'beginners', as there are many factors to consider, ie sense of ensemble, how proficient are you at playing w/ others, ie do you accompany singers and instrumentalists? have you played any chamber works?
you mention a sonata, lots of experience w/ this form and playing them as a whole, i all movements back to back, is essential to grasp the structure, pacing, and make performance decisions based on understanding of theme, development, recap, codas/codettas, etc.
then there is and endurance aspect, how much experience has you attained at working pieces lasting more than say 20 minutes?
beyond the above, or if not there yet, you will be limited to working 'tutorial' type works,ie concertos written specifically for students in lower grades of instructional series, and these are typcially only avail for two pianos, so i would also look at doing works for duet, and piano duo.
if you are looking at a standard, and have a reasonable amount of natural talent, solid instructional resource/good teacher, and are willing to work at it, then i recc what happens to be my most favorite concerto of all time
Kabalevksy 3
prob the most definitive and excellent perf/recording of it here